(See also Alopecia.)
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 is by inspection. Alopecia areata typically manifests as discrete circular patches of hair loss characterized by short broken hairs at the margins, which 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.
If therapy is considered, intralesional corticosteroid injection is the treatment of choice in adults. Triamcinolone acetonide suspension (typically in doses of 0.1 to 3 mL of 2.5 to 5 mg/mL concentration every 4 to 8 weeks) can be injected intradermally if the lesions are small. Potent topical corticosteroids (eg, clobetasol propionate 0.05% foam, gel, or ointment 2 times a day for about 4 weeks) can be used; however, they often do not penetrate to the depth of the hair bulb where the inflammatory process is located. Oral corticosteroids are effective, but hair loss often recurs after cessation of therapy and adverse effects limit use.
Topical anthralin cream (0.5 to 1% applied for 10 to 20 minutes daily then washed off; contact time titrated as tolerated up to 1 hour/day) may be used to stimulate a mild irritant reaction. Minoxidil 5% solution may be helpful as an adjuvant to corticosteroid or anthralin treatment.
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.
Oral methotrexate has been successfully used for the treatment of alopecia totalis and alopecia universalis in both adult and pediatric populations. Doses range from 15 to 25 mg weekly. 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 due to high relapse rates, lack of randomized controlled trials, and increased risk of cancer with PUVA.
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).
Janus kinase (JAK) inhibitors are a new class of immunomodulator drugs (tofacitinib, ruxolitinib, baricitinib) that in small studies have shown benefit and show promise for treating alopecia areata (2, 3).
Hairpieces and camouflage techniques can be used to mask the effects of hair loss.
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.
Damsky W, King BA: JAK inhibitors in dermatology: The promise of a new drug class. J Am Acad Dermatol 76(4):736-744, 2017. doi: 10.1016/j.jaad.2016.12.005.
Bavart CB, DeNiro KL, Brichta L, et al: Topical Janus kinase inhibitors for the treatment of pediatric alopecia areata. J Am Acad Dermatol 77(1):167-170, 2017. doi: 10.1016/j.jaad.2017.03.024.