Acquired progressive kinking of the hair. Structural changes and growth dynamics of affected hairs

Pediatric Dermatology Photoquiz: A 14‐Year‐Old Boy with Abrupt‐Onset Hair Changes

“…In affected scalp skin, 5‐alpha‐dihydrotestosterone (DHT) levels are higher than in unaffected scalp skin . Trichogram reveals a low anagen:telogen ratio in affected scalp . Hair follicle miniaturization and a terminal:vellus ratio of 3.4:1 are observed, consistent with findings in androgenetic alopecia .…”

“…Acquired progressive kinking of the hair appears to be a precursor to androgenetic alopecia according to histologic and hormonal studies . Scanning electron microscopy reveals hair shaft irregularity, fine tips, and shortening in APKH‐affected hair . In affected scalp skin, 5‐alpha‐dihydrotestosterone (DHT) levels are higher than in unaffected scalp skin .…”

“…In another type, reported in a 10‐year‐old boy, an 8‐year‐old girl, and a 14‐year‐old girl, hair kinking completely regressed with time (reports range from 3 mos to 8 yrs) and was not associated with hair thinning . In yet another type, acquired localized hair kinking remained stable, without obvious associated hair thinning . In evaluating pathologic hair kinking or frizziness, in addition to excluding chemical damage and physical trauma to the hair, determining whether the condition is acquired or congenital is important.…”

Woolly‐Hair Nevus: A Case Report and Study by Scanning Electron Microscopy

“…Post (6) divided woolly hair nevi into three categories: (1) a type in which the glabrous skin and scalp are normal; (2) those associated with a linear epidermal nevus of the skin; and (3) a type acquired in young adult life in which discrete portions of the scalp develop short, dark, and kinky hairs. The acquired form has also been called acquired progressive kinking of scalp hairs (8,11,(14)(15)(16).…”

“…Bovenmeyer (12) demonstrated curved hair follicles in a woolly-hair nevus that he believed to account for the curling of the hair. Follicle morphology may be helpful in differentiating woolly-hair nevus from acquired progressive kinking of scalp hair in which hair roots are straight (14,16). The anagen: telogen ratio measured in a woolly-hair nevus of one patient was found to be normal (1).…”