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Clinical and histologic findings in temporal triangular alopecia
C Trakimas1, L C Sperling, H G Skelton
1Dermatology Service, Walter Reed Army Medical Center, Washington, DC 20307.
Background:
Temporal triangular alopecia (TTA; also called "congenital triangular alopecia") is a common disorder that is assumed to be congenital. Little is known about its histologic features.
Objective:
Our purpose was to describe four new cases, review the literature, and present histologic features based on vertical and transverse sectioning.
Methods:
The history, clinical features, and histologic findings of four patients with TTA are described and the relevant literature reviewed.
Results:
Lesions of TTA are seldom congenital, and most are best described as lancet-shaped. The "bald spot" contains normal numbers of hairs, although virtually all are vellus or indeterminate follicles.
Conclusion:
Most cases of TTA appear to develop during the first few years of life, and the designation "congenital" is a misnomer. The appearance of alopecia can be best explained as a focal zone of hair miniaturization leading to vellus hair formation.