Article Type

Original Study


Objectives The aim of the study was to compare between clinical examination, skin scraping, and histopathological examinat ion in the diagnosis of scabies and assess the role of immune cells (CD4+ and CD8+) and transforming growth factor b (TGF-b) to differentiate between scabietic and nonscabietic patients. Background Scabies is a contagious skin infection characterized clinically by nocturnal pruritus and visible burrows. Scabies can occur in epidemic or endemic form. Scabies is still a major public health problem in many resource-poor regions, with prevalence rates reaching up to 10% in the general population and 50% in children. The diagnosis of scabies is challenging, leading to the observation that scabies is at once the easiest and most difficult diagnosis in medicine. Patients and methods Physical examination, skin scraping, and histopathological analysis were carried out for diagnosing scabies. Biopsies were taken from untreated skin lesions of patients 35 with scabies, six with psoriasis, eight with lichen planus and eight normal individuals. T-cell subsets (CD4+ and CD8+) and anti-inflammatory cytokine (TGF-b) were evaluated by immunohistochemical analysis. Results Skin scraping and histopathological examination were highly specific (100%) when compared with physical examination, but the sensitivity of histopathology (88%) was superior to scraping (23%) and clinical diagnosis (85.6%). The highest number of CD4+ T cells was found in scabies and lichen planus but not in psoriasis. In contrast, the highest number of CD8+ T cells was found in psoriasis but not in scabies or lichen planus. There was statistically significant difference between scabietic and nonscabietic patients with regard to CD4+, CD8+, and CD4+/CD8+ ratio. Mild expression of TGF-b was observed in patients with scabies compared with moderate to strong expression in lichen planus and psoriasis. Conclusion Histopathology is an accurate diagnostic method but recommended in suspicious cases only as it is an invasive technique. A high number of CD4+ cells and low expression of TGF-b are characteristic of scabietic lesions.