Understanding a skin rash on the chest

A rash beneath clothing, jewellery or a fragrance product may indicate contact irritation or allergy. Fine red spots after sweating can fit heat rash. Moist skin beneath the breasts or across a fold can become inflamed as intertrigo. Scaly plaques may occur with psoriasis, while an expanding ring can be fungal. A rash that begins soon after a new medicine deserves a medication review.

Keep the chest cool, gently cleanse after sweating, and pat folds dry. Choose loose breathable clothing and pause newly introduced fragranced products or jewellery. Avoid scratching and sharing towels. Photograph the rash before applying treatment, and record its onset, spread, sensations and recent medicines so a clinician can compare the pattern.

Seek urgent care for trouble breathing, swelling of the lips or tongue, faintness, rapidly blistering or peeling skin, severe pain, purple spots, or sores in the mouth or eyes. Arrange prompt assessment if the rash spreads quickly, becomes hot or tender, or produces pus or a foul odour.

Could sweat, friction, a product, infection or a medicine explain this pattern? Does a skin fold need specific care? Should I avoid any product or medicine? What symptoms would make this urgent?