7 Most Common Skin Diseases in Africa

The importance of skin diseases is often overlooked. They are usually not life threatening and tend to be “shrugged away”. Skin diseases are, however, a significant problem all over the world.

Nowadays many skin diseases are related to or influenced by concomitant HIV infection. These conditions are presented rather than other, rare skin diseases.

There are many more congenital malformations and syndromes, benign and malignant tumours, tropical infections, skin manifestations of systemic and metabolic disease, auto-immune diseases etc. which are important but fall outside the context of this article as they are not common.

On the other hand some common skin diseases like myiasis and jiggers are not included because they seldom reach a clinic, people know how to deal with them.

Needless to say, when you are in doubt about a diagnosis the patient should be referred to a skin specialist. When care is taken to make the proper diagnosis and to institute the proper treatment the management of skin diseases often results in great improvement and satisfaction for patient and health care worker alike. Treatments required generally need not be expensive and are locally available.

The patient with a skin problem

A patient who presents with a skin problem often complains of “itchy rash all over the body”. Indeed many patients are referred to the skin clinic with “itchy rash all over the body” as a diagnosis.

After taking a history and performing a proper skin examination you may find he or she is suffering from anything as varied as eczema, urticaria, a drug reaction, a skin infection, scabies or any other skin disease.

A proper skin examination should be performed in good light, preferably daylight. Ideally the whole skin should be examined. The aspect, extent and localization of all the lesions is essential for making a diagnosis and will influence your management.

Eczema
- Atopic Eczema
- Pityriasis Alba
- Infantile Eczema
- Seborrhoic Eczema
- Lichen Simplex
- Infective Eczema
- Contact Eczema
Fungal / Yeast Infections
- Mycids
- Tinea Corporis
- Tinea Capitis
- Tinea Unguium
- Athlete’s Foot
- Pityriasis Versicolor
- Candidiasis
- Mycetoma / Madura Foot
Bacterial Infections
- Impetigo
- Folliculitis
- Folliculitis Keloidalis Nuchae
- Erythrasma
- Secondary Syphilis
- Yaws
- Leprosy
- Leprosy Complications
- Buruli Ulcer
- Noma / Cancrum Oris
Viral Infections
- Hiv Infection
- Pityriasis Rosea
- Chickenpox
- Herpes Zoster
- Herpes Simplex – Lips & Genitals
- Kaposi’s Sarcoma
- Common Warts
- Plantar Warts
- Plane (flat / Juvenile) Warts
- Genital Warts / Condylomata Acuminata
- Molluscum Contagiosum
Parasitic Infections
- Creeping Eruption / Larva Migrans
- Scabies
- Norwegian (crusted) Scabies
- Leishmaniasis
- Lymphatic Filariasis
- Onchocerciasis
Auto-immune Diseases
- Alopecia Areata
- Chronic Bullous Dermatosis Of Childhood
- Chronic Discoid Lupus Erythematodes
- Lichen Planus
- Vitiligo
Miscellaneous Skin Diseases
- Acne Vulgaris
- Albinis
- Dermatosis Papulosa Nigra
- Drug Eruptions
- Hemangioma (congenital)
- Infantile Acropustulosis
- Keloids
- Malignant Melanoma
- Papular Pruritic Eruption
- Pearly Penile Papules
- Porphyria Cutanea Tarda
- Psoriasis
- Urticaria / Papular Urticaria

1. ECZEMA

The terms eczema and dermatitis are often used to describe the same condition. Eczema is a non-infectious inflammation of the skin. It may be acute, sub acute or chronic and is influenced by many factors, i.e. constitutional, irritant (Vaseline, mineral oils, soaps and detergents vegetable oils usually are no problem), allergens, heat, stress, infection etc.

An acute eczema characteristically shows redness, swelling, papules, blisters, oozing and crusts. Progressing to the sub acute stage, the skin is still red but becomes drier and scalier and may show pigment changes. In the chronic stage lichenification, excoriations, scaling and cracks are seen.

There are many different types of eczema, the most common ones will be presented on the following pages. They may have predominantly acute, sub acute or chronic phases. Itching is often the major complaint.

a) ATOPIC ECZEMA

Atopic eczema is a multifactorial skin disease seen in patients with an atopic constitution. This means that they have a genetic pre-disposition for hypersensitivity reactions such as asthma, hay fever and atopic eczema.

The eczema comes and goes and may be triggered or worsened by dryness of the skin, infections, heat, sweating, contact with allergens or irritants and emotional stress.

Atopic eczema in children and adults appears in elbow- and knee-folds, on the wrists and ankles and on the face and neck; in some cases it may become generalized. Itch is an important feature. In long-standing disease lichenification is common

b) PITYRIASIS ALBA

Pityriasis Alba is a mini-form of eczema which occurs predominantly in infants, children and adolescents. Multiple hypopigmented, vaguely bordered, very finely scaling patches are found on the face and/or trunk, and sometimes the extremities.

This can persist for years and the hypopigmentation usually does not clear with steroids, but will clear in time

c) INFANTILE ECZEMA

In infants atopic eczema is often popular and tends to occur on the face and the neck, the trunk, the hands and feet, which may be scratched open causing bacterial super infection.

The major complaint these infants have is itch. Often young infants also have seborrhea eczema especially on the scalp, in the nappy area and body folds. Attempts to differentiate between the two become difficult. For practical purposes the term infantile eczema is therefore used.

In the majority of cases the course is chronic recurrent up to age 2 to 3 years, after which the eczema disappears. In a minority it progresses to childhood or adult atopic eczema

d) SEBORRHOIC ECZEMA

This is eczema with classically greasy scales on seborrhea areas of the skin; scalp, border of forehead/scalp, behind ears, above and in between eyebrows, in nasolabial folds, chin, the sternum, the middle of the upper back in between the shoulder blades, in axilla, groin and perianal area.

Constitutional and stress factors play a role as well as a yeast, pityrosporum ovale, which is found in sebaceous glands. Patients often complain of oily skin as a result of their pronounced sebum production. The eczema comes and goes. In mild cases only the face, scalp and chest are affected.

Sometimes, and commonly in case of immunosuppressant such as in HIV-infected persons the eczema can become very widespread and easily super infected. It occurs in armpits and groin and is conspicuous behind the ears. It may generalize to cover the entire skin.

Usually you will still find the typical greasy scales in e.g. the nasolabial folds. The entire skin is inflamed, red to a darker shade than normal.

e) LICHEN SIMPLEX

In lichen simplex there is one (sometimes more) well-circumscribed patch of lichenified skin which is very itchy. Lichenification means thickening of the skin with exaggerated skin lines and this is usually caused by continuous scratching, rubbing with a stone or stick and the likes.

Patches are commonly seen in the neck, in the genital area and on the lower legs.

f) INFECTIVE ECZEMA

This is an eczema which occurs as a response to an oozing skin infection. The most common localization is the foot/ankle region, especially around the instep.

Causative organisms are usually staphylococci or streptococci. The use of Vaseline often aggravates the condition.

g) CONTACT ECZEMA

Contact eczema is caused by contact of the skin with an irritant or an allergen. Chronic irritant contact eczema is caused by excessive, repeated contact of an irritant with the skin.

Vaseline commonly causes “vaseline dermatitis”, which presents with papules and pustules on the lower legs, often of schoolgirls. Common causes of irritant contact eczema on hands, arms and legs are excessive use of water, soap (especially if not washed off properly after use) and detergents, and many types of chemicals (e.g. alkaline and acid solutions, organic solvents such as alcohol, benzene, toluene, gasoline).

Saliva may cause “lip-licking disease” through repeated wetting of the skin around the lips

2. FUNGAL / YEAST INFECTIONS

Fungal infections may occur at any age. Children may easily infect each other or get infected by animals / pets. The most common fungal infection is “athlete’s foot” = infection of the interdigital spaces of the toes.

Skin, nails and / or hair may be infected. When a fungal infection is treated incompletely or too short it will almost certainly recur. In immunosuppressed patients fungal infections may be more widespread and take longer to treat than normal.

Always ask your patient to come for review when his or her treatment is about to be completed, If you then see any remaining sign of infection continue the treatment, as it is likely to recur if you do not.

a) MYCIDS

A hypermetric reaction to the fungus may occur in the course of fungal infections. These are usually itchy eruptions of small blisters at a site distant from the fungal infection, often the hands and fingers (pompholyx). No fungi are found within these “mycids”.

They disappear when the causative fungal infection is treated. Sometimes the itching is so severe that treatment is advisable: a strong steroid cream under wet dressings for a couple of days

b) TINEA CORPORIS

Fungal infection of the skin, most common on the exposed surfaces of the body, namely the face, arms and shoulders.

Tinea or ringworm presents in typical round lesions, which show scaling at the periphery, or in concentric rings. Usually one or a few lesions are seen and only topical treatment is necessary.

Multiple, large or widespread lesions may be seen if a patient delays seeking treatment for a long time or is malnourished or immunosuppressed.

c) TINEA CAPITIS

Scalp ringworm is common in children. The fungus has grown into the hair follicle and will not be removed by topical treatment only.

Severe pustular forms exist with follicular pustules and nodules and often massive purulent secretion. Lymph nodes in the neck swell and the patient may have a fever and headache. There may be bacterial super infection. Systemic treatment is necessary to prevent scarring leading to permanent bald patches

d) TINEA UNGUIUM

Fungal infection of the nails is common, especially of the toenails in the elderly, where it generally does not require treatment.

There may be a mixed fungal and yeast infection of toenails and /or fingernails. Chronic paronychia is a chronic inflammation of the skin around the nail caused by mixed or yeast infections. It often occurs in people who frequently wet their hands such as domestic workers, cleaners, and kitchen and laundry staff.

e) ATHLETE’S FOOT

Itchy, often macerated whitish scaling lesions and inflammation of the skin in the interdigital spaces of the foot. Most common between the 4th and 5th toe.

The condition is not always caused by fungi but can be caused by bacteria as well. For this reason oral antifungal are often ineffective. The condition is often seen in people wearing rubber boots or rubber / plastic sandshoes.

f) PITYRIASIS VERSICOLOR

This is a common, chronic, superficial fungal infection which is caused by the yeast pityrosporum. It is usually asymptomatic, causing only cosmetic complaints.

Pityrosporum is a normal skin resident predominantly of seborrhea areas which becomes pathogenic under favourable circumstances: warmth and humidity, pregnancy, serious underlying disease or a genetic predisposition.

On the scalp the infection presents as dandruff, from there the neck and upper trunk become infected. Recurrences are common, especially after inadequate treatment or re-infection.

g) CANDIDIASIS

Candida is resident yeast of the mucous membranes. It becomes pathogenic under favourable host conditions. These are:

When host immunity is decreased such as in HIV-infected and cancer patients or by systemic steroids, cytotoxic drugs, and radiotherapy.
Pregnancy and contraceptive pill use.
Warmth and moisture (babies’ nappy area, groins, under breasts, between toes).
Use of broad-spectrum antibiotics which kill resident non-pathogenic bacteria.
Diabetes mellitus.

Candidacies or thrush presents on the skin as red macules often with small pustules on their periphery which break down as the lesion spreads outwards.

On the oral and vulvo-vaginal mucosa redness, superficial erosions and white adherent plaques may be seen. These can be itchy and painful. When oral lesions extend to the throat and esophagus they can cause anorexia. Infection of lips / corners of the mouth also occurs. Severe mucosal candidacies is seen often in HIV infection

h) MYCETOMA / MADURA FOOT

This is a chronic localised infection which can be caused by various species of fungi (eumycetoma) and bacteria, actinomycetes and nocardia (actinomycetoma).

These micro-organisms live in the soil and enter the skin usually after a penetrating injury. The most common localization is therefore the foot or lower leg in barefoot persons but lesions may appear anywhere on the body.

A painless subcutaneous nodule or induration is followed by more nodules which may discharge pus with grains (small hard pinhead sized particles) through fistules, form abscesses and ulcers and spread to underlying bones and joints. The color and hardness of the grain may help in deciding on the causative agent.

3. BACTERIAL INFECTIONS

a) IMPETIGO

This is a very common bacterial skin infection, usually caused by staphylococci and/or streptococci. It presents with superficial pustules or blisters which become oozing erosions with yellow crusts as it spreads.

Impetigo is contagious and may even spread through the shared use of jars of Vaseline. Vaseline application makes it worse.

b) FOLLICULITIS

Folliculitis is an inflammation of hair follicles, usually caused by infection with bacteria, specifically staphylococci. Common localisations are the face, the trunk and the buttocks, but any skin area with hair follicles may be affected.

In HIV-infected patients gram negative bacteria may be implicated or yeast infections, particularly pityrosporon. Folliculitis may be mild and superficial or severe and deep, it may become widespread and very refractive to treatment in immunosuppressed patients.

c) FOLLICULITIS KELOIDALIS NUCHAE

This literally means “keloid-forming folliculitis of the neck”. It may start after the neck is shaved. It is a common condition in African males. A deep folliculitis, usually caused by staphylococci progresses to a chronic fibrosing folliculitis and peri-folliculitis.

Keloidal scars are produced in the deeper cutaneous tissue. New papules and pustules occur at the rims of the keloid. The course is very chronic.

d) ERYTHRASMA

Erythrasma is caused by Corynebacterium minutissimum. It presents as dry, smooth to slightly creased or scaly, clearly demarcated reddish brown plaques, in the groins, armpits or under the breasts.

It may easily be mistaken for a fungal infection but direct microscopy with KOH is negative for fungal elements. Lesions show red fluorescence when viewed under Wood’s light.

e) SECONDARY SYPHILIS

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. Ask for a history of a primary ulcer on the genital area or elsewhere (lips) 1 to 2 months before the development of the rash. Secondary syphilis presents with a generalized symmetric rash which can mimic almost any other skin condition. A helpful diagnostic symptom is the fact that secondary syphilis is not itchy.

Also palms and soles are usually affected as well as the face. A positive RPR or VDRL screenings test is very likely based on syphilis if confirmed by a positive TPHA (specific for Treponemal antibodies). In yaws endemic areas positivity may however be caused by contact with yaws. Results may be discordant in concomitant HIV-infection.

f) YAWS

Yaws, like syphilis, is caused by a treponema. The primary lesion of yaws (mother yaws) is a wet, easily bleeding, raspberry-like papule or nodule, which disappears after a few weeks leaving an atrophic scar.

When the primary infection is not treated secondary lesions (daughter yaws) may appear as generalised nodules, ulcerations and condylomata. Note: Reactivity to VDRL and TPHA is the same as for syphilis.

g) LEPROSY

Leprosy is an infectious disease caused by Mycobacterium leprae. It is an airborne infection (like tuberculosis) which affects skin and nerves. Leprosy often presents with hypopigmented or slightly erythematous patches on the skin with loss of sensation, and enlarged nerves.

Loss of sensation is tested with a whisk of cotton wool. The skin is touched, not stroked with it. The patient is asked to close his or her eyes and to point at the spot which has been touched. Misreference and certainly “not felt” are diagnostic for leprosy. Nerves which should be checked for enlargement are the great auricular, ulnar and radiocutaneous nerves.

Enlarged nerves are pathognomonic for leprosy. When there are infiltrated patches or papules and nodules skin smears may be positive for M. leprae.

Unlucky patients, those who are diagnosed at later stages with nerve damage may show visible deformities such as facial palsy (an eye cannot close, lagophthalmos, and that side of the face sags) and loss of sensation of hands or feet which show dry skin with or without ulcers. Sometimes fingers are bent or even lost, the grip is gone, the feet drop.

h) LEPROSY COMPLICATIONS

Complications of leprosy are the reactions which cause nerve damage and the sequelae of this nerve damage; loss of sensation and loss of muscle strength, with ulceration and deformity as consequence

i) BURULI ULCER

Buruli ulcer caused by Mycobacterium ulcerans is the third most common mycobacterium disease after tuberculosis and leprosy in non-HIV-infected patients.

The disease first described in Uganda is now endemic in swampy areas in West Africa, but may be seen elsewhere. It is transmitted by mild injuries, the bacillus probably residing in muddy water. Patients are usually children.

j) NOMA / CANCRUM ORIS

Noma is a form of infectious gangrene of the mouth. It is thought to be caused by fusiform bacteria. It usually affects children 2 to 7 years of age. Predisposed are malnourished children, especially those with protein deficiency, hypovitaminosis and recurrent acute infections.

The disease generally starts as peridontitis, then ulcerative stomatitis, always on one side of the mouth. It then progresses to gangrene with extensive sloughing of adjacent tissue and necrosis of bone. The area is foul-smelling and very painful. Untreated patients may die or survive with a severe handicap.

4. VIRAL INFECTIONS

a) HIV INFECTION

Related skin diseases occur throughout the course of HIV infection in 90% of the infected persons. During seroconversion an exanthema may occur together with fever and constitutional symptoms. After seroconversion there will be a period of symptomless HIV infection.

Herpes zoster is an early clinical sign which in young age-groups (under 50 years) is very strongly related to HIV infection. Severe and chronic seborrhoic eczema may also be an early manifestation. Other cutaneous manifestations of HIV infection are molluscum contagiosum, papular pruritic eruption, severe herpes simplex or human papilloma infection, severe bacterial, mycobacterial and fungal infections and Kaposi’s sarcoma.

Infestations such as scabies are more severe. Adverse drug reactions are very common in HIV infection.

b) PITYRIASIS ROSEA

This is probably an ide reaction to a viral infection (“a flu of the skin”). There is sometimes a flu-like prodromal episode. Skin symptoms start with a large “herald patch” or “mother patch” on trunk or arms, which many patients can point out to you.

Soon after, many smaller oval lesions which scale at their borders appear on the trunk and (upper) arms. Typically the lesions take on the direction of the skin lines forming a “Christmas tree pattern” on the back. They generally cause no pain or itch and disappear spontaneously within 2 months.

It is difficult to differentiate between pityriasis rosea and secondary syphilis, therefore serological tests for syphilis should always be performed.

c) CHICKENPOX

Chickenpox or varicella is a primary infection with the varicella-zoster virus. It is a common, very contagious infection in children. After a mild prodrome with sometimes fever and malaise the exanthema appears suddenly.

Red macules, papules and shortly thereafter vesicles, pustules and crusts develop on the trunk, scalp and mucous membranes, less so on extremities and face. New crops of lesions appear over the next few days and lesions in all stages of development are seen at the same time. Itch is the main complaint.

Scratching is the main cause of bacterial superinfection and may cause scarring. Crusts fall off in 1-3 weeks. Signs, symptoms and complications become more severe with age.

In adults, fever and constitutional symptoms practically always precede the exanthem. Possible complications include nephritis, myositis, otitis and meningo-encephalitis. In immunocompromised persons chickenpox becomes a life-threatening disease.

d) HERPES ZOSTER

Herpes zoster or shingles is the recrudescence of a latent varicella-zoster infection in the partially immune host. After a short period of itch, tenderness or pain along one or occasionally several dermatomes on one side of the body papules and plaques appear which quickly change into blisters.

Most often thoracic and cervical dermatomes are affected. If the ophthalmic branch of the trigeminal nerve is involved a keratoconjunctivitis may develop and can lead to blindness. After 1-2 weeks crusts begin to fall off. Over 10% of patients develop post-herpetic neuralgia, a persistent burning sensation or pain in the area which has healed. This can last from a few months to many years.

Herpes zoster may appear in otherwise healthy persons, especially the elderly, but is much more common in people with underlying malignancies and HIV-infection. It is an early indicator of HIV-infection in young people. Delayed healing, dissemination and complications are more common a severe in immunocompromised persons.

e) HERPES SIMPLEX – LIPS & GENITALS

The common presentations of a herpes simplex virus infection are the “cold sores” or “fever blisters” on the lip (herpes labialis) and the genital herpes infection. After a few days of prodromal burning sensation, a group of blisters appear which quickly break down to form superficial ulcers.

The primary infection may be accompanied by constitutional symptoms such as fever, malaise and anorexia and take up to 3 weeks to heal. If recurrences occur symptoms are less severe, usually without constitutional symptoms and they heal within 7 to 10 days.

In most people they too are preceded by a burning sensation for a few days. Recurrences are triggered by:

exposure to sunlight (herpes labialis)
trauma (e.g. fighting-lip; sexual intercourse-genitals)
fever People with immunodeficiency as in HIV infection may have more severe infections and more frequent recurrences.

Genital herpes may become chronic, persisting for months, ulcerating and may cover large parts of the genitals and surrounding skin, causing severe pain and disability. Herpes simplex infection is spread by direct contact. It is highly contagious when lesions are visible and it has been shown that people shed virus even when there are no symptoms.

f) KAPOSI’S SARCOMA

The incidence of Kaposi’s sarcoma (KS) has increased dramatically with the current HIV epidemic. Although cases of classic (endemic) KS still occur, the vast majority we see today is HIV-related. KS, which has now been related to the oncogenic Human Herpes Virus-8, is a tumour of the cells of the vascular wall of blood and lymph vessels. Classic KS presents as purple-black papules and plaques usually on one leg which progress very slowly or remain stationary, even over 20 years or more.

HIV related KS progresses much faster and more aggressively. HIV-related KS often presents with generalised lymph node enlargement or pleural lesions. Purple-black nodules and plaques appear on the face, the trunk, the genitalia or the proximal limbs, especially the thighs.

Lesions may also be warty, tumorous, may ulcerate and they may cause gross oedema, especially in the face and of the penis and scrotum. Infiltration of the skin makes it “as hard as wood” on palpation. Plaques, nodules and tumours in the mouth, especially on the hard palate and tonsils are very common, always examine the mouth of a suspected KS patient.

g) COMMON WARTS

Warts are caused by infection with Human papilloma virus (HPV). There are many types of HPV which cause different types of warts.

They are found at any age but are most common in teenagers. They can spread by contact or auto-inoculation. The infected person’s immune system clears the warts within 2 years in 2/3 of cases so treatment is often unnecessary.

Treatment results vary greatly. In some people there is instant success, in others it may take many months or have no success at all. In immunodeficiency warts may spread quickly and fulminantly and become extremely difficult to treat.

h) PLANTAR WARTS

These are also common and they usually give no complaints. When this is the case they are best left alone. Sometimes they cause pain or discomfort urging the patient to seek treatment. It is then best to recommend non-aggressive therapy

i) PLANE (FLAT / JUVENILE) WARTS

These warts usually occur on the face in children and may spread to the upper trunk and arms or rarely to other parts of the body. They are very small (1-3 mm) slightly raised (palpate them!) papules which tend to present in large numbers.

They exhibit a positive Koebner phenomenon which means that they appear in scratched or otherwise traumatised skin. In most children they eventually clear spontaneously. Plane warts usually do not appear in adults but may do so in large num bers when they are immunocompromised, as in HIV infection

j) GENITAL WARTS / CONDYLOMATA ACUMINATA

Condylomata acuminate or genital warts are caused by HPV and are transmitted by direct contact, usually through sexual intercourse, sometimes by infected hands.

Transmission is also possible from mother to child during childbirth. Genital warts may show accelerated growth in pregnancy followed by spontaneous reduction after childbirth. Excessive growth occurs in immune suppressed patients. Patients should have syphilis serology checked. Women with genital warts should have a Pap smear taken.

k) MOLLUSCUM CONTAGIOSUM

These infectious dome-shaped papules are caused by a pox-virus. They have a central dimple in which often typical whitish cheesy material can be seen, it looks like a little white ball.

Molluscum normally occurs in small children in areas of warmth, moisture and friction such as the armpits and the groins, and on the face. Generally they are self-limiting and will disappear within a year without treatment. If they persist for a longer time or if they cause complaints they may be treated.

When they occur in adults, particularly when there are multiple and large lesions, there may be immunosuppression.

5. PARASITIC INFECTIONS

a) CREEPING ERUPTION / LARVA MIGRANS

The larvae of hookworms of cats and dogs usually cause this disease. They enter the skin accidentally and migrate through the skin leaving a very itchy, winding red trail of inflamed skin behind them. Larvae may travel 1 to 5 cm or more daily.

Sites of penetration are those in contact with the ground, usually the feet or especially in small children the thighs and buttocks. The larva can also be transmitted via towels or clothes, which have been in contact with the infected soil. Scratching often causes secondary infection and eczema. If untreated, the larvae eventually die after some weeks or months.

b) SCABIES

Scabies is an infection caused by the mite Sarcoptes scabiei, which lives and moves in the skin producing burrows (S-shaped ridges), small blisters and papules.

Itching is especially severe at night, and causes scratch marks and very commonly secondary infection with pustules and crusts. Lesions occur preferentially between the fingers, on the sides of the hands and feet, on the flexor sides of the wrists, in the armpits and on the genitals and buttocks.

In infants and small children palms, soles, head and neck are often affected. Scabies is primarily spread through close personal contact but may be transmitted through clothing, linen, or towels.

c) NORWEGIAN (CRUSTED) SCABIES

This is a variant of scabies where the skin lesions are extremely massive and extensive. Thick, grey keratoses and crusts develop on the hands, elbows, knees and ankle joints and also extend to areas not normally affected by scabies such as the face and scalp, and nail beds.

Norwegian scabies is seen in severely immunocompromised patients such as in AIDS patients. The crusts are teeming with scabies mites and thus very infective to others.

d) LEISHMANIASIS

Leishmaniasis is caused by an infection with the leis mania parasite, after the bite of an infected sandfly. After an incubation period of two weeks to four months an erythematous or skin colored nodule appears. This ulcerates and then becomes crusted or even verrucous, in most cases eventually leaving an ugly scar.

The sandfly likes to bite on moist areas, preferably around the eyes, ears, nose and mouth. Lesions may be found on the skin, the mucous membranes or both. The latter, mucocutaneous leismaniasis, may completely destroy the nose and does not heal spontaneously.

Leishmaniasis may cause lymphadenitis or become visceral, Kala Azar. After Kala Azar it may cause PKDL, Post Kala Azar Dermal Leishmaniasis. In a few cases leishmaniasis becomes generalised, showing infiltration and nodules over the whole body. This persists for life.

e) LYMPHATIC FILARIASIS

Elephantiasis in the tropics may have a number of causes ranging from bacterial or fungal lymphangitis and adenitis to Price’s disease. In the latter silicates in red volcanic soil which enter the skin through the soles cause an immune reaction which blocks the lymph nodes.

A common cause of elephantiasis is the parasitic worm Wuchereria Bancrofti, which is transmitted by mosquitoes. It presents after an incubation period of 5 to 15 months with mild lymphangitis and lymphadenitis, and pitting oedema of one or more extremities or genitals.

The lymphadenitis is descending rather than ascending. At first there are attacks of swelling but later the symptoms become chronic. Adult worms are present in the lymphatics and the resulting inflammatory response is thought to be the cause of the obstruction.

The late effects include firm lymphoedema of the extremities, the vulva, scrotum, arms and breasts. The legs at this stage often have a warty appearance with folds and cracks in the lower legs and feet. Active infection can be diagnosed with a rapid card test using fingerprick blood.

f) ONCHOCERCIASIS

Onchocerciasis or river blindness is a chronic infection of the skin and the eyes by the filaria Onchocercus volvulus. It is transmitted by female blackflies which are typically found near fast moving water.

People living in these areas get infected again and again, thereby accumulating hundreds to thousands of microfilariae in the skin and the eyes, where they move around freely. In the skin this causes severe itch as the major presenting complaint. In the first stages there are only a few erythematous hyperpigmented papules and scratch marks. Later the whole skin thickens and becomes dry and lichenified.

There is loss of elasticity (hanging groins). Skin hyper-, hypo- and depigmentation may occur in chronic cases. Onchonodules, which represent the adult worms, can be seen and palpated, in particular above the hipbones but also elsewhere. Biopsy or skin snip may show microfilariae.

Eye involvement is a well known cause of blindness. If the history is suspect but microfilariae have not been demonstrated a Mazotti test can be performed. Under careful conditions (cave: anaphylactic shock) 50-100 mg diethylcarbamazepine (DEC, Hetrazan) is given. A positive test yields intolerable itch within a few hours.

6. AUTO-IMMUNE DISEASES

a) ALOPECIA AREATA

Alopecia areata occurs in adults and in children and generally presents as one or more round or oval bald patches on the scalp or beard area.

The hair is lost suddenly, the bald patch extends until it is usually some centimeters in diameter, and as a rule after weeks to months new hairs begin to grow within the lesion. The skin remains normal, showing hairfollicle openings without scaling or atrophy.

The re-growing hair may be white in color, giving the impression of “turning white overnight” when a large area is affected. In progressive cases new bald patches develop as others heal, or patches do not heal for years. In alopecia areata totalis there is baldness of the whole head; in alopecia areata universalis all body hair including scalp, beard, eyebrows, eyelashes, pubic and axillary hair falls out.

b) CHRONIC BULLOUS DERMATOSIS OF CHILDHOOD

This is a chronic blistering disease which occurs in children. It usually starts before the age of 5 years. Small and large blisters appear predominantly on the lower trunk, genital area and thighs, often also on the scalp and around the mouth. They may spread all over the body.

New blisters form around healing old blisters, forming “a cluster of jewels”. There is often some itchiness. The course is chronic, spontaneous remisSion usually occurs after an average of 3-4 years.

c) CHRONIC DISCOID LUPUS ERYTHEMATODES

Chronic discoid lupus erythematodes (CDLE) is a chronic scarring skin disease which occurs on sun-exposed areas. The face is the commonest site, but scalp, upper trunk and distal extremities may also be affected.

On the face there may be a “butterfly distribution” on the cheeks and bridge of the nose, the lips may also be affected. The lesions are welldefined reddish patches with thick or hyperkeratotic scaling and hyper-, hypo- or depigmentation, they feel rough on palpation.

They slowly increase in size and form atrophic hypopigmented scars. Exposure to sunlight aggravates the lesions and causes an increase in symptoms, such as itch and irritation.

d) LICHEN PLANUS

Lichen planus presents with very typical itchy papules, which are small (1-3 mm) and are demarcated by the natural skin lines, making them polygonal. They have a sharp, elevated border, a flat surface (hence the name “planus”) and they shine by reflecting light. They are often a shade of red, later reddish blue to purple and show “Wickham’s striae”, a fine milky-white network on the papule’s flat surface.

Neighbouring papules may join together to form plaques which resemble lichen growing on trees, explaining the name “lichen”. They may occur anywhere on the skin but are most common on joint flexures (especially wrists), genitals, sacral region and inner thighs.

A Koebner phenomenon is present. The oral mucosa and lips may be affected and show a network of white lines. Actinic lichen planus occurs on sun-exposed areas. In hypertrophic lichen planus there are thick, hyperkeratotic papules and nodules or thickened wart-like plaques on the shins. Lichen planus is self-limiting, it will disappear spontaneously, s

e) VITILIGO

Vitiligo is a relatively common, sometimes familial disorder in which depigmentation of the skin occurs. It may start at any age but often starts in young adults.

Lesions start as small white macules and become progressively larger and confluent, leading to bizarre shapes. Common localisations are the hands and feet and the skin around body openings, e.g. around the eyes, nose, mouth and lips, the umbilicus, and around the genitals and the anus. Vitiligo also occurs in traumatised skin and can affect hair bulbs, leading to streaks of white hair.

The condition is usually slowly progressive and seldom regresses spontaneously. Vitiligo of the genital area should be distinguished from lichen sclerosis, in which depigmentation and atrophy are usually limited to this area.

7. MISCELLANEOUS SKIN DISEASES

a) ACNE VULGARIS

Acne is very common in puberty and it usually regresses in early adulthood. Sometimes it persists up to age 30 or lifelong. Sebum production (patients complain of “oily skin”) is the most important factor in acne.

It occurs on the face and the upper trunk as blocked sebaceous gland ducts (forming comedones= blackheads and whiteheads), which may progress to inflammatory papules, pustules and nodules. Acne may be very mild to very severe.

In severe acne conglobata, acne lesions blend together to form large inflammatory areas with cysts and scar formation

b) ALBINIS

Albinism is an inherited disorder of melanocytes, which do not synthesise melanin (pigment). This results in absence of pigmentation of skin, hair and eyes, combined with photophobia and nystagmus from birth.

The skin is white, the hair white or yellow and the iris light blue. These patients are very light sensitive because they have no UVabsorbing melanin, which usually protects people from solar damage.

After short term sun exposure sunburn, freckling, and early ageing of the skin already occurs and actinic keratoses with a tendency towards malignant transformation appear. Squamous cell carcinoma is seen at an early age, even in children.

c) DERMATOSIS PAPULOSA NIGRA

A very common papular eruption in Africans which is probably genetically determined. Dark brown to black papules appear on the upper part of the face, especially on the cheeks and the temples.

The first papules may appear from early teens and they increase in number with age. Forty percent of Africans over 30 years of age have this eruption in a limited or extensive form. It is more common in women than in men.

d) DRUG ERUPTIONS

Most common are maculo-papular exanthemas, which are usually itchy. Drugs with a > 1‰ incidence of drug-induced exanthema are: penicillins, sulphonamides (fansidar, trimethoprim), NSAID’s (like aspirin, indomethacin), isoniazid, erythromycin, hydantoin derivatives (e.g. phenytoin), carbamazepine, allopurinol, streptomycin and gold salts.

They may occur soon after taking the drug (in previously sensitised patients), on finishing a course of drugs, or up to 3 weeks after taking a drug. Urticaria is also a common reaction, often caused by penicillins, NSAID’s, acetylsalicylic acid and X-ray contrast media.

Fixed drug eruptions recur on exactly the same spot every time the responsible drug is taken. There is usually one, sometimes two or more macules or plaques, reddish-purple in colour. They may show blistering and leave persistent hyperpigmentation on healing.

Most frequent causes: barbiturates, paracetamol, pyrazolon derivatives, sulphonamides and tetracyclines

e) HEMANGIOMA (CONGENITAL)

Congenital hemangioma’s are benign tumours of blood vessels which become manifest in the first few days of life. They can be single or multiple and vary in size from less than 1 cm to more than 10 cm. The preferred site is the face though they can occur anywhere on the skin.

The mucous membranes i.e. the lip and tongue can be affected. Hemangioma’s may grow rapidly in the first months causing great concern to the parents.

However, they regress spontaneously in about 70% of the patients. Regression starts in the first year of life and takes 5-10 years. Sometimes a hemangioma may bleed easily or it may become (partly) necrotic after trauma or during a period of fast regression.

Regression may show no scarring, there may be a slack, baggy area of skin if the hemangioma was large or the skin may be hypopigmented and atrophic

f) INFANTILE ACROPUSTULOSIS

Infantile acropustulosis is a condition of unknown cause which occurs in infants, usually under the age of 1 year. Intensely itchy vesicles which quickly progress to pustules appear on the soles and the sides of the feet and on the palms, often in the first 3 months of life.

The pustules last for one to several weeks and then subside only to reappear two to four weeks later. Attacks recur with diminishing severity and frequency in time and stay away at the end of the second or third year. The pustules are sterile and the condition does not warrant antibiotic treatment, which is a common misconception. Anti scabies treatment is also ineffective.

The condition often seems to appear after successful treatment of scabies, which should make you wonder whether it was scabies which was treated in the first place.

g) KELOIDS

Keloids are fibrous tumours caused by overgrowth of connective tissue. They usually occur in a scar, weeks to months after the skin is traumatised.

The keloid spreads beyond the boundary of the original injury to form a hard, irregular, shiny, sometimes painful or itchy ridge or plaque. In primary keloids there is no apparent preceding trauma.

Once formed keloids remain stationary for years after which, some become partially flattened. They are especially common in Africans

h) MALIGNANT MELANOMA

This is a very malignant tumour which in Africans usually arises on the foot, less often on the hand (usually acro-lentiginous melanoma). It can start as a small pigmented papule or nodule which grows, often showing typical blue-grey-black shades of color, and sometimes bleeding or ulcerating.

It spreads to other organs rapidly and the diagnosis is often made when the tumour has already spread to at least regional lymph nodes and it is too late for cure.

Early diagnosis is therefore important. Keep a melanoma in mind when someone presents with a chronic ulcer on the foot especially when it shows typical pigmentation or when it does not respond to ulcer-treatment. An incision biopsy should not be performed in a lesion which is suspect for malignant melanoma, the lesion needs to be excised in total.

i) PAPULAR PRURITIC ERUPTION

The phrase “papular pruritic eruption” defines an itchy, persistent or chronic recurrent rash which is found in HIV-infected patients and for which no other cause (e.g. urticaria, scabies, folliculitis etc.) can be found.

There are usually widespread inflammatory papules, hyperpigmented scars and scratch marks. The patient may or may not show other signs of HIV-infection.

j) PEARLY PENILE PAPULES

Pearly penile papules are not a disease, they are an anatomical variant. Small, usually whitish or skin colored papules are found at the border of the glans penis, just before the coronary sulcus.

They are very regularly spaced and regular in size. They are often a great worry to young men who think they have penile warts or another sexually transmitted infection and may have caused them to seek all sorts of treatments

k) PORPHYRIA CUTANEA TARDA

Porphyria cutanea tarda is a chronic disturbance of the metabolism of porphyrins, manifested by liver damage and skin lesions. The disease affects more men than women, generally over the age of 40.

Skin which is exposed to the sun is affected, mainly the face and the backs of the hands. Exposure to sunlight or trauma induces small blisters which lead to erosions, crusts, atrophy, flat or depressed scars and pigmentation changes. Milia are often present. Increased hairgrowth is also a feature.

The urine of these patients is red in color after sun exposure due to increased porphyry excretion

l) PSORIASIS

Psoriasis is a chronic recurrent, inherited, non-infectious skin disease caused by an abnormally fast turnover of the epidermis. The turnover may be up to 40 times the normal and as a result the epidermis is not able to develop normally. All layers become too thick and the most obvious one is the horny layer, the outer layer of the skin. The skin is red, inflamed, and the scales are thicker than normal.

They produce a so-called candlewax phenomenon: when you scratch such a patch it becomes silverywhite. Psoriasis also displays a Koebner phenomenon, i.e. it appears in traumatised skin.

Classical psoriasis occurs on the scalp, the extensor areas of extremities (esp. elbows, knees), the umbilicus and the buttocks. Finger- and toenails may show pitting, thickening of the nailbed or distal onycholysis (brownish oil-like changes on the distal nail where the nail is detached from the nailbed). Palms and soles may also show thickening; callus, scales and cracks. Treatment is often effective but you can never cure the patient of the disease as such. It may always recur, after weeks, months or years.

Psoriasis may flare up after an infection (flu, angina) or drug use (e.g. antimalarial drugs, beta blockers, lithium). There is also a pustular psoriasis and an inverse form with lesions in skin folds rather than extensor areas, the latter may be difficult to distinguish from seborrhoic eczema.

Psoriatic arthritis of the small joints of the hands and feet occurs in 5- 10% of patients. The arthritis may be mutilating and eventually become widespread.

m) URTICARIA / PAPULAR URTICARIA

Urticaria is a reactive phenomenon which is characterized by itching wheals (hives). These may be any shape or size, appear anywhere on the body and as angioedema in the face, at any interval.

Sometimes there is a single attack of urticaria, sometimes there are attacks every few hours. Urticaria may come and go during a few days or persist for many years.

There are many types of urticaria and possible causes of urticaria: contact urticaria (e.g. stinging nettles, caterpillars, formaldehyde); physical urticaria (cold, heat, pressure); cholinergic urticaria (sweat, exerciseinduced); Drug-induced non-allergic urticaria (aspirin, pethidine, morphine, hydralazine); allergic urticaria by drugs (see drug eruptions), food (fish, milk, nuts, tomatoes, citrus fruits, cocoa, strawberries), insect allergens (bee, wasp), vaccines, worm infestations, and internal diseases.

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