Outcome of facial rashes with non-specific histological features: a long-term follow-up of 64 cases.

Facial inflammatory dermatoses can be difficult to diagnose in their early stages; skin biopsy may help but often shows indeterminate features. The aims of our study were to identify patients presenting with a facial dermatosis requiring skin biopsy, in whom the initial histological features were classified as "non-specific", to determine the eventual diagnostic outcome, and to attempt to identify subtle early histologic features. We located 79 such cases with indeterminate histology from 45,000 dermatopathology reports 1972-1987. The original biopsies were assessed and scored using a check-list of 20 features and the patients' case-records up to 1992 were examined. Follow-up information was available in 64 cases and an eventual clinical diagnosis was made in 54 (84%) of these; the commonest diagnoses were rosacea (26%), chronic discoid lupus erythematosus (24%) and seborrheic or unclassified dermatitis (17%). Histological differences were seen in the original biopsies of these three diagnostic categories, although none was predictive. We conclude that clinical follow-up leads to the diagnosis of most facial rashes initially showing "non-specific" histology.