The presence of loose anagen hairs obtained by hair pull in the normal population.

To help determine the specificity of "loose anagen" (LA) hairs in Loose Anagen Syndrome, the presence or absence of LA hairs on a gentle but firm hair pull was evaluated in 110 normal subjects from a 0.5 to 83 y old. In children < or =10 y old, 61% had LA hairs on hair pull evaluation and 73% of all hairs obtained were LA hairs. In contrast, LA hairs were found in only two of 87 (2%) normal postpubescent subjects. The number of LA hairs was small in normal children (1-2 per hair pull) and a maximum of one out of every 6-7 hair pulls in adults, far less than that reported with Loose Anagen Syndrome. Although the mere presence of LA hairs on a hair pull test is thus not specific for LAS in children, the number per hair pull may have diagnostic significance. Correlation of these findings with the various hair disorder phenotypes currently termed Loose Anagen Syndrome will be important.