Clinical and Sequential Histopathological Study of Scabietic and Postscabietic Nodules


ABSTRACT:BACKGROUND:Scabietic nodules are common problem seen before and after effective therapy of scabies that might persist for months.OBJECTIVE:To evaluates the clinical and histopathological features of these nodules during their sequential course.PATIENTS AND METHODS:Patients with scabietic nodules were enrolled in this study. Five (14.7%) patients had active scabies at the time of consultation. All recruited patients had personal and family history of treated scabies with persistent itchy nodules. Patients were fully examined for: sites, numbers and sizes of the persistent scabietic nodules. Histopathological evaluation was done from nodules in patients with active scabies before therapy and at different times during the course of the post-scabietic nodules . RESULTS:Thirty four male patients were studied with mean age (34.41±16.72) years. The lesions were more prevalent in young adult age group 20-29 (24.5±2.9) years. The nodules had persisted for a period ranged from 1-52(13.47±14.29) weeks. Intolerable itching was evident in all these nodules but without the nocturnal accentuation. The number of nodules ranged from 1-35(8.5±6.8) lesions. These nodules were more heavily involving: scrotum in 20(28.57%) patients and penile shaft 19 (27.14%), and less commonly involving the upper thigh, lower abdomen, axilla and penile corona. Differential white blood cells count revealed normal eosinophilic count in all patients with post scabeitic nodules, while high values were observed in 4out of 5 patients with active scabies.The histopathology of scabietic and post-scabietic nodules revealed: acanthotic epidermis with mild spongiosis, pseudoepithelial hyperplasia present in 2(5.8%) nodules. The infiltrate was mainly diffuse (papillary and reticular dermis) dense lymphocytic in 29 (85.2%) nodules and even in early stages, the density of the infiltrate decline when the nodules persisted more than 6 months. Scattered eosinophils were present in the dermis of all nodules regardless the age of nodule. Mild lymphocytic vasculitis recognized in 3 (8.8%) nodules in patients with short duration (3-9 weeks). Granulomatous reaction with Langhans giant and epitheliod cells was another important finding in4 (11.7%) nodules.CONCLUSION:Scabietic nodules tend to affect male adult with a predilection to the scrotum and penile shaft. The histopathological pictures consisted mainly of acanthotic epidermis and diffuse dense dermal lymphocytic infiltrate in 85% of scabietic nodules. No mites or mite parts could be detected. Lymphocytic vasculitis and granulomatous reactions present in few nodules.