What should you know about prickly bumps on skin?

Small itchy or prickling bumps in sweaty or covered areas can fit heat rash. Bumps centred on hairs, especially with tenderness or pus, can fit folliculitis. Rough bumps on the outer upper arms or thighs may be keratosis pilaris, while firm pearly spots can be milia. Lichen planus has a different pattern and may cause itchy, purplish or scaly lesions.

Look at when the bumps began, whether they follow heat or friction, and whether they spread. A photograph taken in good light can help a clinician compare changes, but self-diagnosis from appearance alone is unreliable.

Keep the area cool and dry, wear loose breathable clothing, and wash gently without scrubbing. Pause new fragranced products and avoid squeezing or scratching. If shaving or friction preceded the flare, allow the skin to settle before repeating that activity.

A pharmacist or clinician can advise whether an antihistamine is appropriate for itch. Persistent, recurrent, painful, scaly, or spreading bumps may need an examination because treatment differs between folliculitis, heat rash, keratosis pilaris, milia, and inflammatory conditions.

Arrange prompt medical review for rapidly spreading redness, increasing warmth, severe pain, pus, fever, facial or eye involvement, or sores that do not heal. Seek urgent help for breathing difficulty or swelling of the lips or tongue with the rash.

Are the bumps centred on follicles, blocked sweat ducts, or another type of lesion? Could a medicine, product, heat exposure, or infection be contributing, and what should I use or avoid while the diagnosis is being clarified?