Female pattern alopecia in Child
The youngest case of female pattern alopecia in the literature is a six-year-old female. Although data on prevalence is lacking, a retrospective study of 438 pediatric patients presenting with hair loss reported androgenetic alopecia as the second most common cause of alopecia in males and females after exclusion of tinea capitis diagnoses, with alopecia areata as the most prevalent diagnosis. However, in this case series, androgenetic alopecia surpassed alopecia areata as the most common cause of hair loss in the 12-19-year-old cohort (42% of 123 patients).
The pathophysiology of female pattern alopecia is poorly understood, and it is unclear how pathophysiology differs between pediatric and adult populations. The role of androgens in female pattern alopecia is less clear than that in male pattern alopecia, and the majority of females diagnosed with female pattern alopecia do not show biochemical or clinical signs of hyperandrogenism. Similarly, although genetics are believed to predispose patients to female pattern alopecia, the role of family history is less clear than that in male pattern alopecia. In the pediatric population, approximately 75% of patients with androgenetic alopecia have one parent with androgenetic alopecia and 25% have two parents with androgenetic alopecia.
The distribution of hair loss in female pattern alopecia is different than that in male pattern alopecia. Patients present with diffuse central thinning and widening of the middle part. This is described as a "Christmas tree pattern" when patients present with frontal accentuation. Patients may also present with bitemporal thinning. Frontotemporal recession and thinning at the vertex, as seen in male pattern alopecia, are less common. Areas of absolute baldness are also uncommon. Interestingly, both males and females in the pediatric population commonly present with the female pattern. In adolescence, male patients are more likely to present with the male pattern, although the female pattern can be seen. Pediatric patients with androgenetic alopecia often have other dermatologic diagnoses, such as acne and atopic dermatitis. Seborrheic dermatitis of the scalp is also commonly present in cases of androgenetic alopecia.
L64.9 – Androgenic alopecia, unspecified
1108009 – Female pattern alopecia
Differential Diagnosis & Pitfalls
- Tinea capitis – Acute presentation with patchy hair loss associated with pruritus. Physical examination shows erythematous patches with scale and black dots indicating broken hair shafts. Kerions are common in patients aged 5-10 years. Posterior cervical lymphadenopathy increases suspicion of the diagnosis.
- Alopecia areata – Well-demarcated hair loss, often in round and band-like distributions.
- Anagen effluvium – Acute onset hair loss days to weeks after an inciting event. Significant alopecia results, as approximately 90% of hair is in anagen at a given time.
- Telogen effluvium – Acute onset hair loss usually occurring 3-4 months after an inciting event. A positive hair-pull test is suggestive of the diagnosis.
- Loose anagen syndrome
- Short anagen syndrome – Presents as abnormally short hair in children aged 2-4 years with positive hair-pull test.
- Hypotrichosis simplex – Possible genetic basis, presents with sparse or normal hair at birth with onset of hair loss at puberty.
- Marie-Unna hypotrichosis – Autosomal dominant inheritance, presents as sparse hair at birth with further hair loss during puberty.
- Monilethrix – Possible genetic basis, presents as sparse hair that grows slowly.
- Trichotillomania – Presents as focal patches of nonscarring alopecia with irregular borders and broken hair shafts of varying lengths.
- Traction alopecia – Examination commonly shows hair loss along the temporal hairline with "fringe sign" and tenting of hair follicles.
- Discoid lupus erythematosus – Erythematous scaly plaques that lead to scarring alopecia of the scalp. Uncommon in the pediatric population.
- Drug-induced alopecia