Davener's dermatosis: A variant of friction hypermelanosis

Background: As part of our clinical experience we encountered a group of patients from a specific population with a similar peculiar pigmentation over the lower dorsal spine. Objective: We investigated these patients to see whether we could determine a common origin. Methods: Patients meeting the inclusion criteria underwent detailed history and complete physical examination; biopsy specimens from 3 patients were studied. Results: All 13 patients were full-time male students at Orthodox Jewish Talmudic seminaries (Yeshivas). The lesion consisted of an elongated, vertical, midline, hyperpigmented patch with indistinct borders, which was distributed along the skin overlying the bony protuberances of the inferior thoracic and lumbar vertebrae. It was often unrecognized by the patients. Mean body mass index was lower than that for the general population. Histologic study showed a marked diffuse hyperkeratosis and hyperplastic epidermis with diffuse hyperpigmentation. We attributed the phenomenon to friction from the rigid backrests against the cutaneous surface of the lower back generated by the characteristic swaying activity that traditionally accompanies Torah study or 'davening' (praying) and termed it Davener's dermatosis. Conclusion: We believe this phenomenon represents a new form of benign friction hypermelanosis. This report highlights the importance of a thorough history in patients presenting with pigmented lesions.