What causes alopecia areata?

The follicles are usually not destroyed, which is why regrowth remains possible. The precise trigger for an individual episode often cannot be identified, and the condition is not the result of poor hygiene or something another person can catch.

Hair follicles normally cycle through growth and rest. In alopecia areata, immune cells mistakenly target follicles and interrupt active hair production. This commonly produces smooth, clearly defined bald patches, but the pattern may become more extensive or involve brows, lashes, beard hair and body hair.

Genes can contribute to susceptibility, yet alopecia areata is not inherited in a simple, predictable way. Some people notice an episode after illness or emotional strain, but timing alone does not prove that stress caused it. Many people cannot identify any event before the first patch appears.

Have new patchy hair loss assessed rather than assuming the cause. A clinician can look for the smooth non-scarring pattern, examine the nails, and check for scale, broken hairs or inflammation that may suggest infection, traction or another form of alopecia. A biopsy or blood testing is reserved for situations where the examination or health history raises a specific question.

Protect exposed scalp with shade or sunscreen and handle remaining hair gently. Treatment decisions depend on the number and location of patches, how quickly loss is changing, age, previous response and personal priorities. Options may include observation, corticosteroids placed on or into the skin, or systemic treatment for more extensive disease.

Request a timely appointment if patches are enlarging, several areas appear close together, or eyebrows and eyelashes are being lost. Pain, marked redness, scale, crusting, pus or a scar-like surface are not features to dismiss; they may indicate a different diagnosis that needs specific treatment. Sudden hair loss with other unexplained health changes should also be discussed with a clinician.

Ask what visible signs make alopecia areata the likely diagnosis, whether another cause needs exclusion, and whether any test would change management. Mention autoimmune conditions in yourself or close relatives, new medicines, scalp symptoms and recent illness, while recognising that none of these details automatically identifies a single trigger.