[Crusted (Norwegian) scabies in Dakar (Senegal)]

Between January 1993 and June 1997, 30 patients with crusted scabies were seen at the dermatological clinic in Dakar (Senegal). Seventeen of these patients were male and 13 were female. Six were children aged 5 to 15 years and 24 were adults aged 18 to 70 years. Diagnosis of crusted scabies was straightforward because this condition, which was rare in Dakar before 1990, has become much more common and is now familiar to Senegalese dermatologists. The infection presented as an extensive scaly or crusted eruption with symmetrical lesions affecting the hands, feet, knees, elbows and ears in particular. Scalp involvement was reported in 25 patients. Erythrodermia was present in 4 cases and pachyonychia in 4 cases. Twenty-seven of the 30 patients had moderate or severe pruritus, whereas an absence of pruritus is regarded as a classical characteristic of crusted scabies. Diagnosis was readily confirmed by examination of hyperkeratotic material under the microscope: numerous mites and eggs were present. The two most common etiological factors were auto-immune diseases (6 cases, 4 of whom were receiving no steroid or other immunosuppressive treatment at the time of onset of crusted scabies) and malnutrition (5 of the 6 children in the study). The other associated conditions identified were: physical debilitation (4 cases), HIV infection (3), mental disability-Down's syndrome (3) and long term use of topical steroids for artificial depigmentation (2). Two patients were immunocompetent and 5 patients died shortly after diagnosis, before any underlying conditions could be identified. Seven patients were cured with benzyl benzoate. Seven others, all adults, received a single oral dose of ivermectin (200 mg/kg) and topical kerolytic drugs. Ivermectin was ineffective in 1 case, and an improvement was observed in another case, although a complete cure was achieved only after a second dose. The other patients were all cured and showed no signs of scabies one month after ivermectin treatment. A recurrence was observed in 3 patients a few months later however, suggesting that these patients were reinfected. No side effects were reported in any of the patients treated with ivermectin.