Small hard red bump on arm: what should you know?

Folliculitis is inflammation around a hair follicle and can produce small red, tender, or itchy bumps, sometimes after shaving, sweating, or friction. Keratosis pilaris causes rough, firm follicle-centred bumps, often on the outer upper arms, and may feel like sandpaper. These conditions can coexist with dry skin. A single painful bump that becomes warm or develops pus may behave more like a boil. The colour and texture alone do not identify one diagnosis.

Notice whether there are many similar bumps or one isolated lesion, whether hairs are centred in them, and whether the area is spreading.

Wash with a mild cleanser, avoid scrubbing and picking, and reduce tight clothing or repeated friction. Moisturising can help rough follicle bumps; introduce any exfoliating product gently and stop if burning or worsening redness occurs. Avoid sharing towels or razors if bumps are draining. Arrange a review when the problem keeps returning, does not settle, or leaves painful nodules or marks, because treatment differs between folliculitis and keratosis pilaris.

Seek prompt care if redness expands, the skin becomes hot and very painful, pus collects, or fever develops. Urgent assessment is appropriate for red streaks, rapidly increasing swelling, severe pain, or feeling faint or unwell. A bump that remains unchanged for a long time or repeatedly bleeds also deserves examination.

Ask whether the bumps fit folliculitis, keratosis pilaris, or another condition, and whether a product, shaving habit, or medication may be contributing. Ask how long to try gentle care and what signs indicate infection or the need for prescription treatment.