Brown bump on the skin: possible causes

A raised brown spot may follow an inflamed follicle, insect bite, heat irritation, or healing blemish. Folliculitis can produce tender or itchy bumps around hairs. Keratosis pilaris often feels rough and may cluster on the upper arms or thighs. Milia are small, firm cysts, while lichen planus can cause itchy, violaceous-brown bumps. The colour may reflect pigment left after inflammation rather than the original cause. A clinician considers whether the bump is soft, scaly, smooth, painful, or filled with fluid.

Keep the area clean, avoid picking or squeezing it, and pause fragranced products that sting. Loose clothing can reduce rubbing and heat-related irritation. Note when it appeared, whether it follows shaving, and whether it changes with sun or sweating. A dermatologist may recommend targeted treatment such as an oral antihistamine for itch or cryotherapy for a diagnosed, suitable lesion. Do not freeze an unexplained bump at home, because the treatment can obscure important changes and injure surrounding skin.

Book a skin assessment if the bump persists, enlarges, repeatedly bleeds, becomes painful, crusts, ulcerates, or changes in colour or outline. Seek prompt care for rapid change, spreading redness with fever, or marked swelling. A bump that is new and unlike your other spots deserves attention even when it causes little discomfort.

Does the bump arise from a follicle, cyst, rash, or another skin growth? Do I need a dermoscopic examination? What should I photograph or monitor, and would treatment risk a darker mark?