Causes of Hot Tub Rash

The rash may appear after swimming as red, itchy, or tender bumps around hairs, especially beneath a swimsuit where wet fabric holds water against the skin. Warm, poorly maintained water can allow germs to multiply. A reaction to disinfectant or fragrance may cause broader itching where the product touched. Heat rash forms in sweaty areas, while atopic dermatitis, contact dermatitis, ringworm, scabies, psoriasis, or intertrigo may have different distributions and surface changes.

Rinse with clean water, remove the swimsuit, wash gently, and dry the skin rather than scrubbing it. Wear loose clothing and avoid another hot-tub session until the rash has settled. Do not share towels or pick at bumps. Take a photo and note when the rash began, where it is located, and whether anyone else who used the water is affected; this helps a clinician distinguish infection from irritation.

Arrange an assessment if the rash spreads, becomes increasingly painful, drains pus, forms blisters, or does not start settling. Seek prompt care for fever, chills, marked weakness, facial or eye involvement, or a rapidly expanding red area. Emergency help is needed for swelling of the lips or throat or difficulty breathing.

Ask whether the bumps look infectious or irritant, whether a swab is needed, which products or pools to avoid, and when it is safe to swim again.