Vulvovaginal and common prepubertal gynaecological disorders: Viva

Branch 1: Confirming the diagnosis

The candidate should recognise the presentation as classic paediatric lichen sclerosus, a chronic inflammatory dermatosis of unknown cause that presents with intense pruritus, soreness, and the characteristic porcelain-white, atrophic, wrinkled plaques in the figure-of-eight distribution around the vulva and the anus. [8] The small purpuric spots are typical of the active disease, in which the fragile sclerotic skin bruises and tears with minimal trauma. The diagnosis is clinical in the great majority of cases and rests on the recognition of this distribution and this appearance. [10]

If the examiner presses on the differential diagnosis, the candidate must distinguish lichen sclerosus from vulval vitiligo, which is depigmented but not atrophic or pruritic, from atopic or contact dermatitis, which is erythematous and itchy but lacks the porcelain-white sclerosis, and from the bruising and scarring of sexual abuse. [10] A skin biopsy confirming the epidermal atrophy, the basement membrane thickening, the upper dermal collagen homogenisation, and the band of lymphocytic inflammation is reserved for cases where the diagnosis is uncertain or the condition does not respond to an appropriate course of treatment. [9]