Davener's dermatosis: A variant of friction hypermelanosis

Background: As part of our clinical experience we encountered a group of pa tients 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 s tudied. Results: All 13 patients were full-time male students at Orthodox Jewish Ta lmudic seminaries (Yeshivas). The lesion consisted of an elongated, vertica l, midline, hyperpigmented patch with indistinct borders, which was distrib uted along the skin overlying the bony protuberances of the inferior thorac ic and lumbar vertebrae. It was often unrecognized by the patients. Mean bo dy mass index was lower than that for the general population. Histologic st udy showed a marked diffuse hyperkeratosis and hyperplastic epidermis with diffuse hyperpigmentation. We attributed the phenomenon to friction from th e rigid backrests against the cutaneous surface of the lower back generated by the characteristic swaying activity that traditionally accompanies Tora h study or "davening" (praying) and termed it Dnvener's nei dermatosis. Conclusion: We believe this phenomenon represents a new form of benign fric tion hypermelanosis. This report highlights the importance of a thorough hi story in patients presenting with pigmented lesions.