4.2.1 Alopecia Areata
Grading & Level of Importance: B
Spot baldness, patchy alopecia, autoimmune hair loss.
Reversible, non-scarring, usually localised but also generalized hair loss.
Aetiology & Pathogenesis
Present in all ethnic populations. May affect 0.1% of the population.
Autoimmune process with lymphocytic T-helper and T-cytotoxic cell subsets infiltrate around anagen hair bulb. Association with other autoimmune diseases; Down syndrome.
Signs & Symptoms
Macroscopically non-inflamed, non-scarring loss of hair in circular shapes with solitary, multiple or diffuse patterns. Exclamation mark hairs. Sometimes associated nail changes (pitting) or complete nail loss.
Most easily identified in hairy areas such as the scalp or beard region, or body hair.
According to extent of hair loss:
Alopecia areata: solitary or multiple areas of hair loss.
Alopecia totalis: loss of all scalp hairs.
Alopecia universalis: loss of all scalp and body hairs.
Laboratory & other workups
Association with atopy with increased IgE (worse prognosis) and autoimmune thyroiditis (TAK /MAK). Syphilis serology (where there are multiple small patches clinically) to exclude moth-eaten alopecia of secondary syphilis. Fungal culture if diagnostic doubt. Anti-streptokinase titre.
Not usually required. Perifollicular lymphocytic infiltrate around anagen follicles with apoptosis of follicular keratinocytes and formation of dystrophic hair shafts.
Focal lesions have a high spontaneous remission rate (30% within 6 months, 50% with 1 year, 80% within 3 years). Widespread disease has low spontaneous remission rate (Factors conveying a poor prognosis include positive family history, involvement of occipital scalp hairline (ophiasis type), widespread disease, longer duration (onset in childhood) and atopy.
Loss of eyebrows and eyelashes with chronic conjunctivitis, nail involvement (twenty nail dystrophy), association with autoimmune thyroiditis, vitiligo, pernicious anemia (other autoimmune disorders less common), psychosocial problems with persistent alopecia are common.
Clinical diagnosis in most cases.
Prevention & Therapy
Await spontaneous regrowth. Small lesions can be treated with high-potency topical corticosteroids or intralesional corticosteroids. More widespread forms may respond to topical immunotherapy with diphenylcyclopropenone. In severe cases, systemic corticosteroid pulsed therapy can be considered. Other evidence-based treatment are not available but third line treatments may include methotrexate, zinc and phototherapy. Wigs, permanent make-up for eyebrows and self-help groups.
- Which of these factors contribute to the etiology of alopecia areata?
- Alopecia areata is an autoimmune disease characterized histologically by a peribulbar lymphocytic infiltrate which precedes the hair loss. The hair follicles are not destroyed so regrowth is possible. Alopecia areata can involve:
- Statement 1 If the lesion is small, at least 80% of patches of alopecia areata regrow within 3 years.
- Which of these methods are appropriate for treating alopecia areata?
- This 45-year-old patient comes to you because his barber found this lesion, which is asymptomatic. Your diagnosis?
- True or false?
- This 10-year-old boy with hay fever has experienced hair loss for the past month. Your diagnosis?
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