Allergic characteristics of urban schoolchildren with atopic eczema in Ghana.

BACKGROUND: Atopic eczema is an increasing clinical problem in Africa. OBJECTIVE: To determine allergic characteristics and to identify possible risk factors for eczema among schoolchildren in an urbanized area in Ghana. PATIENTS AND METHODS: Schoolchildren aged 3-16 years with eczema were recruited. For each patient, one to three age- and sex-matched controls were selected. All children completed a questionnaire and were skin prick tested with a panel of allergens. Blood was drawn to determine the total and allergen-specific IgE. Conditional logistic regression models with the matching factors included in the model were used to calculate the odds ratios and to adjust for possible confounders. RESULTS: A total of 52 children with eczema (27 boys and 25 girls) and 99 controls were included. Levels of total IgE were found to be 9.1 (1.1; 78.4) times more often elevated in children with eczema. This association was mainly driven by elevated IgE levels against cockroach antigen. Children with eczema were found to have 2.0 (0.87; 4.7) times more often positive skin prick tests (SPT), but this association diminished to 1.2 (0.40; 3.6) after adjustment for total IgE levels. Frequent washing with soap was identified as a risk factor for the development of eczema among these children. CONCLUSION: Schoolchildren with eczema in Ghana were characterized by elevated IgE levels especially against cockroach antigen. The association between eczema and positive SPT was much weaker suggesting immune hyporesponsiveness of the skin. After adjustment for IgE level, SPT were less suitable to distinguish children with and without eczema.

Mycobacterium ulcerans infection (Buruli ulcer) in Ga district of Greater Accra region

A study of 22 subjects affected by Mycobacterium ulcerans (Buruli ulcer) in the Ga District of Greater Accra Region of Ghana; bordering the rivers Densu and Nsaki; is presented. Of these subjects 68.2 per cent were less than 15 years of age with a male to femal ratio of 1.8:1 and 63.6 per cent were either pre-school or school children. 72.7 per cent of the subjects were first affected before the age of 10 years. The distribution of the skin lesions involved the exposed skin areas in 86.4 per cent of cases and contact cases were identified in 50 per cent of the subjects. A complication of squamous cell carcinoma was observed in one subject. The possible modes of transmission are discussed

A survey of skin diseases seen at Korle Bu Teaching Hospital; Accra; Ghana

A survey of 784 consecutive patients seen in the skin clinic at Korle Bu Teaching Hospital; Accra; Ghana is presented. The ratio of males to females was 0.9:1.0. Various skin diseases were seen with dermatitis/eczema being the most common 44.8 per cent while infectious diseases accounted for only 16.8 per cent of the total

Persistence of allergic contact sensitivity in subjects with photosensitivity dermatitis and actinic reticuloid syndrome.

We report the maintenance of allergic contact sensitivity in 20 subjects with photosensitivity dermatitis and actinic reticuloid syndrome. Positive patch test reactions were demonstrated some years after the initial diagnosis and after significant maintained improvement of the photodermatosis had occurred.

Quinine induced photosensitivity: clinical and experimental studies.

Quinine induced photosensitivity, an infrequently described adverse effect, is reported in four patients. The clinical presentation and distribution was that of a light exposed site eruption characterized by oedema and erythema in three patients, and by lichen planus in the fourth. Monochromator phototesting demonstrated abnormal delayed erythema responses in the UVB, UVA and visible wavebands. The clinical features suggested a phototoxic effect but laboratory studies indicated that the molecular mechanisms involved are unusual. Clinical and phototest evidence of abnormal photosensitivity persisted for some months after stopping quinine. Broad spectrum sunscreens are advised for the management of such patients and, where possible, cessation of quinine administration.

Thiazide-induced photosensitivity: a study of 33 subjects.

The clinical features, action spectrum and subsequent course, are described in 33 subjects with thiazide-induced photosensitivity. The reaction appeared to be phototoxic in nature. The wavelengths involved were those of the longer UVA and, not infrequently, also the shorter UVB waveband. In most instances withdrawal of the drug resulted in clearance of the clinical reaction and a return of the action spectrum to normal. In the few subjects in whom the photosensitivity persisted, either in the form of the clinical reaction or an abnormal action spectrum, or both, either a specific photodermatosis was present or another potentially photoactive drug was being taken. In no instance, was there evidence of the induction of long-term chronic photosensitivity (persistent light reaction) following the withdrawal of the thiazide drug.

UVB phototherapy and photochemotherapy (PUVA) in the treatment of polymorphic light eruption and solar urticaria.

Forty subjects (36 with polymorphic light eruption and four with solar urticaria) were treated during the spring and early summer of the years 1982 to 1985 with either UVB phototherapy (a total of 54 treatment courses in subjects with polymorphic light eruption) or photochemotherapy (PUVA) (18 treatment courses in polymorphic light eruption and eight in solar urticaria patients). Both forms of prophylactic therapy were found to be effective in 90% of those with polymorphic light eruption, and PUVA in all those with solar urticaria. The optimum duration of treatment was 5 weeks. Adverse reactions, although common, were usually slight and rarely required alteration of the treatment regimen.

A study of cutaneous photosensitivity induced by amiodarone.

Amiodarone-induced cutaneous photosensitivity was studied in 12 subjects treated with the drug. The action spectrum for the abnormal response to sunlight was shown to be within the range of 335-460 (+/- 30) nm. The clinical features of the photosensitivity response suggested that it was most probably a phototoxic reaction, a conclusion supported by the results of in vitro studies which indicated activity mainly against cell membranes. Of the five in vitro models used, three--namely photohaemolysis, the inhibition of DNA synthesis in PHA stimulated lymphocytes and the killing of mouse peritoneal macrophages--provided unequivocal evidence of the phototoxic potential of both amiodarone and its major metabolite, desethylamiodarone. In each model desethylamiodarone produced a greater effect by a factor of between 2 and 10. In vitro, UV-B wavelengths produced a greater effect than UVA but the difference between the effective wavelengths in vivo and in vitro might be explained by the greater absorption of the shorter wavelength UV-B in the epidermis. Zinc oxide-containing preparations appeared to be the most effective in reducing the cutaneous photosensitivity. It is suggested that the long-term cutaneous pigmentation resulting from oral amiodarone has a significant photosensitivity component.

A study of compositae plant extract reactions in photosensitivity dermatitis.

In subjects with chronic photosensitivity of the photosensitivity dermatitis/actinic reticuloid type the persistent reaction of the skin appears to be due to a number of factors, including those of contact allergic sensitivity and of photosensitivity (i.e., phototoxicity and/or photoallergy). The assessment of the relevant importance of these factors can be complicated by the reactivity of the skin resulting in false positive responses from skin patch and photopatch testing. Moreover, difficulties may also arise in the assessment of the results using commercially available patch test materials. However, the study described here indicated that, provided the reactivity of the skin is suppressed prior to investigation, reliable results are obtained from photopatch testing and that these results are similar whether the extract is from a commercial source or has been obtained from locally grown Compositae plants. Also, that although there may be a photoallergic component in the cutaneous photosensitivity, the results of the in vivo and in vitro studies reported here indicate the likely involvement of phototoxicity as well.

Actinic prurigo--a specific photodermatosis?

Actinic prurigo can be defined as an idiopathic photodermatosis which usually starts in childhood, particularly affects the female, with some evidence for an atopic and familial photosensitivity background. It affects both exposed and covered skin but mainly the former and although it may be present all the year round is usually maximal on the exposed skin during months of sunshine. The changes are those of a chronic prurigo along with more acute episodes following sunshine exposure in which there is a background of edematous erythema. It usually lasts throughout childhood and adolescence, but tends to wane and even to clear in late adolescence or early adult life. The etiology is unknown, as are the mechanisms involved. Action spectrum studies have produced no evidence for the involvement of specific wavelengths other than the presence of UV sensitivity in some subjects and a suggestion that the longer wavelength UVA may be more important than the sunburn waveband around 305 nm. Based on a study of 60 personal cases with actinic prurigo the authors agree with the longheld view of Calnan & Meara (1) that actinic prurigo is a separate and distinct photodermatosis.

The relationship between exposure to fragrance materials and persistent light reaction in the photosensitivity dermatitis with actinic reticuloid syndrome.

Contact allergic sensitivity to allergens such as plants of the Compositae family is a feature of the chronic skin reaction seen in the photosensitivity dermatitis with actinic reticuloid syndrome. In fifty patients with this syndrome an increased incidence of contact allergic sensitivity to some common fragrance materials was demonstrated. Evidence is also presented, both by in vitro and in vivo studies, which indicates that a phototoxic mechanism is involved. The relevance of continued exposure to common allergens and their involvement in photosensitization mechanisms is discussed in an attempt to explain the state of 'persistent light reaction'.