What should you know about heat rash from clothes?

Tight garments, non-breathable fabric, damp workout clothes, and rough seams can keep sweat close to the skin. Heat rash may cause prickling, itching, small bumps, or mild redness where the fabric sits. A rash that follows a particular garment may also be caused by detergent, dye, or an allergic or irritant reaction. These appearances overlap with skin bumps and skin redness, so location, timing, and whether the skin improves after changing clothes help guide an assessment.

Take off damp or tight clothing and cool the skin with a gentle rinse or a clean cool compress. Pat dry and choose loose garments that allow air movement. Wash clothing with a mild fragrance-free detergent, rinse thoroughly, and avoid rewearing sweaty items. Keep nails short and avoid scratching, which can damage the surface and invite infection. Avoid thick ointments, perfumed sprays, and plastic coverings while the skin is hot. If scaling or dryness remains, ask a clinician about emollient therapy; use topical corticosteroids only when a professional recommends the product and application.

Seek medical advice when changing clothes does not help, when the rash returns with different garments, or when it spreads beyond areas of contact. Prompt review is appropriate for pain, pus, crusting, marked swelling, fever, or rapidly worsening redness. Call emergency services for breathing problems or sudden swelling of the face or mouth.

Ask whether the rash is heat-related or a reaction to fabric or laundry products, which materials to avoid, and how to protect the skin during exercise. Describe the garment, the timing, sweating, washing products, and any associated symptoms.