Localized alopecia areata: round, discrete patches of hair loss.
The scalp is smooth without scaling, erythema, or scarring.

DESCRIPTION
A non-scarring hair loss. Typically rapid onset in sharply defined, usually round or oval area. Loss may be diffuse or patchy, or band-like at scalp margins.

HISTORY

1. Most common in children and young adults.
2. Sudden hair loss in areas that are sharply demarcated, 1-4 cm.
3. Eyelashes and beard may be involved, and (rarely) other parts of the body.
4. Total hair loss of the scalp (alopecia totalis) is most frequently in young people; may be accom­panied by cycles of growth and loss.
5. Total hair loss of the body (alopecia universalis) is very rare.
6. Regrowth in 1-3 months; may be followed by loss in other areas.
7. Prognosis for total regrowth, if limited involvement, is good.

PHYSICAL FINDINGS

• Most common pattern: patchy. Other patterns: ophiasis (bandlike loss at scalp margins) and ophiasis inversus (spares scalp periphery, involves crown). Diffuse pattern least common.
• Skin typically very smooth but may have short hair stubs.
• Tapered hairs resembling exclamation points best seen at margin of circular loss.
• New regrowth may be fine and white.
• Diffuse fine nail pitting in up to 30%.
• Biopsy if the clinical presentation not typical. Findings include peribulbar lymphocytes, miniaturized follicles, telogen vellus hair ratio of 1.5:1, and increased telogen and catagen follicles.
• May be associated with thyroid disease, pernicious anemia, Addison disease, vitiligo, lupus erythematosus, ulcerative colitis, diabetes mellitus, Down syndrome.
• Differential diagnosis: trichotillomania, tinea capitus, syphilis, telogen effluvium, diffuse androgenetic alopecia.

TREATMENT

• In most areas, hair regrows and no treatment is needed.
• Group I topical steroids applied twice a day are minimally effective. Used in cycles, such as 2 weeks of treatment, 1 week of no treatment.
• Intradermal injection of triamcinolone acetonide (Kenalog) 2.5-10 mg/mL is effective. Injections may be repeated at 4-week intervals. Atrophy is major side effect. Reserved for patients with a few small areas of hair loss.
• Squaric acid dibutyl ester is used by some specialists, but contact allergy can be severe.
• Intravenous pulse of methylprednisolone may be effective in patients with rapidly progressing, extensive multifocal disease.
• Oral corticosteroid therapy does not prevent spread or relapse of severe alopecia areata. Regrowth is obtained, it is rarely maintained off therapy.
• A hair prosthesis should be considered and encouraged for patients with diffuse loss when emotional distress is high.
• A network of support groups across the country is available to help patients cope: Alopecia Areata Foundation (http://www.alopeciaareata.com).