Examining gene expression in hair follicles may be sufficient to diagnose chronic discoid lupus erythematosus (CDLE), a kind of lupus in the scalp, avoiding invasive and expensive scalp biopsies, a study suggests.

CDLE is the most common type of cutaneous lupus erythematosus (lupus that affects the skin), which can occur as part of systemic lupus erythematosus (SLE) or on its own. People with CDLE often develop lesions on areas that get a lot of sun, including the face, neck, and scalp.

Diagnosing CDLE usually requires biopsy of a lesion, which is not ideal for a number of reasons. The procedure is invasive, stressful for patients, expensive, and requires processing and analysis before a diagnosis can be made, often leading to weeks between a test and a diagnosis, thus necessitating additional visits to the doctor, which take even more time and resources.

Yet these lesions often occur on the scalp, and hair can usually be removed less invasively than skin. Might hair follicles — the cells that grow hair — yield enough information for the diagnosis of CDLE?

To find out, researchers collected four to five hair follicles from seven people with CDLE, as well as from six people with psoriasis, another inflammatory skin condition, and from five people without any notable skin inflammation.

The follicles were collected by plucking hairs with tweezers; the researchers wrote that collecting this many follicles “takes an experienced person five minutes,” as the clinician must ensure that the whole follicle at the base of the hair is collected, not just the hair itself.

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