ETIOLOGY: abnormal compulsion to pull out hail
HISTOPATHOLOGY: marker increase in catagen and telogen hairs, possible follicular damage, pigmented casts, possible trichomalacia, and inflammatory changes usually absent
OTHER CAUSES OF PATCHY ALOPECIA: alopecia areata, tinea capitis, loose anagen syndrome, traction and pressure alopecia, secondary syphilis, tick bite alopecia, aplasia cutis, congenital triangular alopecia, familial focal alopecia, pseudopelade