Itchy rash from the sun: what to know

Tender red skin that feels hot after exposure fits sunburn. Tiny prickly bumps in sweaty or covered areas can be heat rash. An itchy eruption on sun-exposed skin that appears after a delay may be a photosensitivity reaction, sometimes related to a medicine or a product such as fragrance. Contact dermatitis can occur when a product is exposed to sunlight. Eczema may also become irritated by heat and dryness. The rash may spare areas protected by clothing, but patterns differ.

Move into shade, cool the skin with damp compresses, and use a plain moisturiser if the skin is intact. Drink fluids and avoid further sun until the rash settles. Wear tightly woven clothing, a broad-brimmed hat, and use a broad-spectrum sunscreen that suits sensitive skin once the skin is comfortable. Do not pop blisters or apply numbing products to damaged skin. If a new medicine preceded the rash, ask the prescriber before stopping it.

Get urgent help for blistering over a large area, facial swelling, breathing trouble, faintness, confusion, severe pain, fever, or signs of dehydration. Seek prompt advice for pus, spreading warmth, or worsening tenderness. Arrange a review if the eruption returns with small amounts of sun, lasts beyond the expected healing period, or follows a new medicine.

Ask whether the pattern suggests sunburn, heat rash, contact dermatitis, or drug-related photosensitivity; whether any medicine or skincare product is contributing; and what sun protection is appropriate for your skin.