(See also Alopecia.)
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The scalp and beard are most frequently affected, but any hairy area may be involved. Hair loss may affect most or all of the body (alopecia universalis). Alopecia areata is thought to be an autoimmune disorder affecting genetically susceptible people exposed to unclear environmental triggers. It occasionally coexists with autoimmune vitiligo or thyroiditis.
Diagnosis of Alopecia Areata
Examination
Diagnosis of alopecia areata is by inspection. Alopecia areata typically manifests as discrete circular patches of hair loss characterized by short broken hairs at the margins that resemble exclamation points. Nails are sometimes pitted, display longitudinal ridging, or display trachyonychia, a roughness of the nail also seen in lichen planus. Red lunula may also be seen.
Differential diagnosis includes tinea capitis, trichotillomania, traction alopecia, lupus, and secondary syphilis. If findings are equivocal, further testing can be pursued with potassium hydroxide preparation, fungal culture, screening for syphilis, or biopsy. Patients with clinical findings suggesting associated autoimmune diseases (particularly thyroid disease) are tested for those diseases.
Biopsy is occasionally necessary.
Prognosis for Alopecia Areata
Alopecia areata may spontaneously regress, become chronic, or spread diffusely. Risk factors for chronicity include extensive involvement, onset before adolescence, atopy, and involvement of the peripheral temporal and occipital scalp (ophiasis).
Treatment of Alopecia Areata
Corticosteroids
Sometimes topical immunotherapy
baricitinib
Rarely photochemotherapy or psoralen plus ultraviolet A (PUVA)
Use of hairpieces and camouflage techniques
Induction of allergic contact dermatitis using diphenylcyclopropenone or squaric acid dibutylester (topical immunotherapy) leads to hair growth due to unknown mechanisms, but this treatment is best reserved for patients with diffuse involvement who have not responded to other therapies.
Methotrexate can also be used in combination with oral corticosteroids. Its use is typically reserved for refractory alopecia areata in patients who fail standard therapy (1).
Systemic and topical PUVA have been used with limited success in patients who fail conventional therapy. However, this is a less favored treatment option because of high relapse rates, lack of randomized controlled trials, and increased risk of cancer with PUVA.
Hairpieces and camouflage techniques can be used to mask the effects of hair loss.
Treatment reference
1. Strazzulla LC, Wang EHC, Avila L, et al: Alopecia areata: An appraisal of new treatment approaches and overview of current therapies. J Am Acad Dermatol 78(1):15-24, 2018. doi: 10.1016/j.jaad.2017.04.1142
