Are there any specific investigations I should consider for a patient with suspected alopecia areata?

For a patient with suspected alopecia areata, there are no routine specific laboratory investigations required in primary care to confirm the diagnosis, as it is primarily clinical based on characteristic patchy hair loss NICE CKS. However, if the diagnosis is uncertain, referral to a dermatologist for further assessment including a scalp biopsy may be appropriate to confirm the diagnosis and assess the degree of inflammation and hair cycle changes NICE CKS.

Basic blood tests are not routinely indicated solely for alopecia areata, but considering the autoimmune nature of the condition, assessment for associated autoimmune diseases (such as thyroid dysfunction) may be considered if clinically suspected NICE CKS,NICE NG145. Thyroid function tests can be relevant since autoimmune thyroid disease can coexist with alopecia areata NICE NG145.

Recent literature supports that alopecia areata is an autoimmune condition with complex pathophysiology, but does not currently recommend additional specific investigations beyond clinical evaluation and specialist referral when diagnosis is uncertain or treatment response is inadequate Fukuyama et al. 2022Alhanshali et al. 2023.

In summary, the key investigations to consider are:

• Clinical assessment primarily for diagnosis.
• Referral for scalp biopsy if diagnosis is unclear or if hair loss does not respond to treatment in primary care NICE CKS.
• Thyroid function tests if there are clinical features suggestive of thyroid disease NICE NG145.

Other investigations are generally not required unless there are atypical features or suspicion of other underlying conditions.