How can I differentiate between alopecia areata and other types of hair loss in a primary care setting?

To differentiate alopecia areata from other types of hair loss in primary care, focus on the clinical presentation and pattern of hair loss.

• Alopecia areata typically presents as well-demarcated, round or oval patches of sudden hair loss on the scalp or other hair-bearing areas, often with smooth, non-scarring skin in the affected areas. The hair loss is usually patchy and may show 'exclamation mark' hairs at the periphery of the patches.
• In contrast, male pattern hair loss (androgenetic alopecia) usually shows a gradual thinning and recession of hair, especially at the temples and crown, with a characteristic pattern rather than discrete patches.
• Hair regrowth in alopecia areata may initially be fine and depigmented before returning to normal colour, which is not typical in other hair loss types.
• If the diagnosis is uncertain, or if hair loss does not respond to initial treatment, referral to a dermatologist for further assessment including possible scalp biopsy is recommended.
• Additional features such as nail changes (pitting) and a personal or family history of autoimmune conditions may support a diagnosis of alopecia areata.

In summary, the key differentiating features in primary care are the sudden onset of well-defined patchy hair loss with smooth skin, presence of exclamation mark hairs, and possible nail changes, distinguishing alopecia areata from patterned or diffuse hair loss seen in other conditions.

Referral to dermatology is advised if diagnosis is uncertain or if treatment response is inadequate.

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