What to know when a bald spot is getting bigger

Growth of the patch does not identify the cause by itself. A clinician can inspect the skin, remaining hairs and follicle openings, then decide whether testing or treatment is appropriate.

A smooth round or oval patch can occur with alopecia areata, an immune-related condition that often presents with patchy hair loss on the scalp or beard. Scale, broken hairs, crusting, itch or tenderness can accompany scalp ringworm. Tight hairstyles, repeated pulling, inflammation and scarring disorders can also produce a widening area.

The surface matters as much as the size. Smooth skin with visible follicle openings suggests a different process from shiny skin where openings seem absent. Diagnosis from a photograph alone can be unreliable because early patterns overlap.

Photograph the spot in the same lighting and from the same angle every few days, placing a comb nearby for scale without pressing it into irritated skin. Note when enlargement began and whether there is shedding elsewhere, itching, scale, pain, recent illness, new medication, or a change in hair styling.

Avoid tight braids, extensions, scratching, harsh chemicals and very hot styling over the area. Do not share combs, hats, pillowcases or towels if scaling or broken hairs raise concern for a contagious fungal infection. Avoid starting steroid or antifungal products at random, as the wrong product may alter the appearance without treating the cause.

Arrange a prompt appointment if the spot continues expanding, new patches appear, or the skin becomes scaly, inflamed, painful or shiny. Seek urgent assessment for rapidly increasing swelling, pus, spreading redness, fever, or a very tender boggy area, since these features can signal a significant infection.

Children with a scaly bald patch should be assessed promptly because scalp fungal infection generally needs prescription treatment. Earlier evaluation also matters when follicle openings seem to be disappearing, as scarring hair loss can damage follicles.

Ask which features support the leading diagnosis, whether hairs or scale should be examined for fungus, and whether the pattern suggests inflammation around follicles. Also ask how progress should be photographed, what scalp products to avoid, and what change should trigger an earlier follow-up.