Background: The epidemiology of alopecia areata (AA) is well documented in adults but has not been studied adequately in children.
Objective: To evaluate the clinical and epidemiological profile of AA in children and assess the significance of thyroid screening.
Methods: One hundred and fifty-seven children (83 boys, 74 girls, aged 1-16 years) who visited our clinic with a first episode of AA from 1996 to 2000 were retrospectively studied. One hundred children served as clinical controls.
Results: The age of peak incidence of AA was 0-5 years. The youngest child was 1 year old. In the majority of the cases (131/157, 83.4%) the disease was mild or moderate (less than 50% hair loss). In 15 patients (9.5%), AA was preceded by a stressful event. Five patients had a personal history of autoimmune disease (3.2 vs. 5% of the controls, (P = not significant [NS]) while 18 patients had a personal history of atopy (11.4 vs. 18% of the controls, P = NS). Twenty-one patients had a family history of autoimmune disease other than thyroiditis (13.4 vs. 5% of the controls, P = 0.04), while 23 patients had a family history of thyroid disorder (14.6 vs. 3% of the controls, P = 0.006). In eight patients (5%) subclinical hypothyroidism of autoimmune aetiology (Hashimoto's thyroiditis) was revealed at the time of investigation. Six out of the eight patients with Hashimoto's thyroiditis had a family history of thyroid disorder, which was statistically significant when compared to AA patients without thyroiditis (P < 0.001). The severity of AA was associated with early age of onset of the disease (P = 0.02).
Conclusion: The age of peak incidence of AA in children is 0-5 years. Children with AA have an increased family history of autoimmunity, and, among children with a first episode and short duration of AA (< 6 months), thyroid screening might be restricted in those with a positive family history of thyroid disorder. Thyroid screening should be routinely performed in all children with long-standing AA.