Bald spots on a man's head

A smooth round patch can be a presentation of alopecia areata. Scale, itch, tenderness, crusting or snapped hairs raise other possibilities, including infection or inflammation. Pressure, tight hairstyles, repeated friction and hair pulling can also create a localised area of loss.

Typical male-pattern hair loss develops gradually at the temples, frontal hairline or crown rather than appearing overnight as a completely bare circle. A patch with normal-looking skin behaves differently from one that is red, thickened or flaky. Short hairs of unequal length may reflect breakage rather than loss from the root.

Look beyond the single spot. Similar areas in the beard, changes in the nails, scalp pustules or enlarged tender glands can help a clinician separate immune-related loss from infection and mechanical damage. A diagnosis cannot be made from shape alone.

Avoid close shaving over irritated skin, harsh chemicals and tight headwear that rubs the same point. Do not share combs, clippers, hats or towels if there is scale or itch. A photograph showing the whole scalp and another close view can reveal whether the patch is widening.

Schedule an appointment if the area continues to expand, remains unexplained or is accompanied by beard or eyebrow loss. The examination may include a magnified look at hairs and follicles; material from a scaly area may be checked for fungus. The correct treatment follows the cause, so borrowed creams and leftover tablets are poor substitutes for assessment.

Obtain prompt care when the patch is painful, boggy, draining pus or surrounded by rapidly spreading redness, especially with fever. Early review is also sensible when the surface becomes shiny and scar-like, follicle openings disappear or hair loss accelerates across several areas.

Ask whether the pattern fits gradual androgen-related thinning or a separate patchy disorder. Other useful questions cover signs of fungal infection, the need to examine beard and nails, whether current medicines matter and how progress should be photographed.