Pemphigus scalp lesions: is trichoscopy helpful in clinical diagnosis?

Pemphigus is an autoimmune intraepidermal bullous disease which can affect skin and∕or mucous membranes. Trichoscopy is a non-invasive tool that can help in the clinical diagnosis especially if the patient is presented with only scalp lesions. We conducted this study to investigate the trichoscopic features of pemphigus scalp lesions.

A total of 100 patients with confirmed diagnosis of pemphigus entered the study; Seventy-nine patients were diagnosed as pemphigus vulgaris (PV) and 21 as pemphigus foliaceus (PF). Trichoscopy of the scalp lesions was performed, and three dermatologists examined separately the trichoscopic images of each patient. The results were re-checked simultaneously by the examiners. Association between variables was analyzed by using different tests including: chi-square test or Fischer's exact test, independent T-Test or Mann-Whitney nonparametric test and logistic regression model when applicable.

Mean age of the patients was 45.41 ± 11.13 years, and 58% of cases were male. The most common trichoscopic features observed among all cases were diffuse scaling (71/100), presence of any types of vessels (67/100), and extravasation (63/100). Positive anagen pull test, extravasation, yellow hemorrhagic crust, and polymorphic vessels were more commonly seen in PV than PF cases (P value < 0.05), and by having data of these variables, we can differentiate between PV and PF scalp lesions with 74% sensitivity and 91% specificity.

Trichoscopy can help in clinical diagnosis of pemphigus scalp lesions but should be followed by other modalities such as biopsy and direct immunofluorescence for definite diagnosis.