In an infant with a temporal‑front hair recession that appears like androgenetic alopecia, what are the likely causes, how should it be evaluated, and what management is recommended?

Temporal Hair Recession in Infants

Temporal-frontal hair recession in infants is a normal physiological phenomenon called "temporal triangular alopecia" or "congenital triangular alopecia," not androgenetic alopecia, and requires only reassurance without any treatment or laboratory evaluation. 1

Key Distinguishing Features

Clinical presentation:

• Temporal recession in infants appears as symmetrical triangular areas of fine, vellus hair or complete hair absence at the frontotemporal scalp 1
• This pattern is present from birth or develops in early infancy, distinguishing it from acquired hair loss 2
• The affected areas contain miniaturized vellus hairs rather than complete follicle absence 1

Why this is NOT androgenetic alopecia:

• True androgenetic alopecia requires circulating androgens and genetic predisposition, which are absent in prepubertal children 3, 4
• Pediatric androgenetic alopecia, when it occurs, presents in adolescence (mean age 15.3 years) with diffuse crown thinning and preserved frontal hairline—not isolated temporal recession 5
• Androgenetic alopecia in children is associated with signs of hyperandrogenism: early body odor, axillary/pubic hair, accelerated growth, and advanced bone age 6

Evaluation Approach

Clinical examination only:

• Examine the scalp for the characteristic triangular pattern at temporal regions 1
• Look for any signs of androgen excess: body odor, pubic/axillary hair, genital maturation, or accelerated growth 6
• Assess for alternative diagnoses: patchy loss with exclamation-mark hairs (alopecia areata), scalp inflammation/scaling (tinea capitis), or diffuse shedding (telogen effluvium) 1, 7

Laboratory testing is NOT indicated:

• Routine endocrinologic evaluation is not recommended for the majority of patients with apparent hair loss 6
• Testing is only warranted when clinical signs of hyperandrogenism are present: early-onset body odor, axillary or pubic hair, accelerated growth, advanced bone age, or genital maturation 6
• Growth charts and hand radiograph for bone age serve as screening tools before any hormonal testing 6

Management

Reassurance is the only intervention needed:

• Temporal triangular alopecia is a benign developmental variant requiring no treatment 1
• The condition is permanent but cosmetically insignificant and typically covered by surrounding hair as the child grows 1
• No medical therapy (minoxidil, finasteride) is appropriate or approved for infants 8

Critical Pitfalls to Avoid

Do not order hormonal panels in healthy infants with isolated temporal recession:

• Routine endocrinologic testing adds no value when clinical signs of androgen excess are absent 6
• Extensive autoimmune panels are unnecessary for straightforward cases 1

Do not confuse normal temporal recession with pathologic alopecia:

• Alopecia areata shows discrete patches with exclamation-mark hairs on dermoscopy, not bilateral temporal thinning 1, 7
• Tinea capitis presents with scalp inflammation, scaling, and requires fungal culture 1, 7
• Telogen effluvium causes diffuse shedding across the entire scalp, not localized temporal loss 1, 7

Recognize when to investigate further:

• If temporal recession is accompanied by signs of precocious puberty (body odor, pubic hair, accelerated growth), obtain growth charts and consider bone age radiograph before hormonal testing 6
• If the pattern is atypical (unilateral, progressive, or associated with scalp changes), consider dermoscopy or dermatology referral 1