Splitting hairs: the 'hamburger sign' in trichotillomania.

BACKGROUND

A 43-year-old male presented with the clinical findings of patchy alopecia that contained persistent hair and re-growth of hairs of various lengths, consistent with trichotillomania. A biopsy was performed to confirm the diagnosis..

RESULTS

Histologic evaluation revealed findings consistent with trichotillomania, including trichomalacia. Several hair shafts also showed a vertically oriented split, which contained proteinaceous material and erythrocytes. Morphologically, these were reminiscent of a hamburger within a bun.

CONCLUSIONS

The unusual finding reported in this case has not been previously reported. The "hamburger bun sign" provides an additional clue to traumatic injury in the evaluation of biopsies for trichotillomania.