Does heat rash itch?

What does heat rash feel and look like?

Heat rash usually causes small raised spots, an itchy or prickly feeling, and mild swelling. Some spots contain fluid. The rash often looks red on white skin, but can look grey or white and be harder to see on brown or black skin. The name 'prickly heat' is unusually direct for skincare, describing the sensation rather than promising a new face.2

Heat rash commonly develops where clothing covers the skin or skin folds touch, including the underarms, under the breasts and inner thighs. It can happen in cool weather too, particularly with overdressing or prolonged bedrest. Babies and children can have the same symptoms as adults. Heat rash can spread across the body, but it is not contagious.23

Why does heat rash itch?

Sweat normally travels through narrow ducts to the skin's surface. When those ducts become blocked, trapped sweat causes inflammation, producing the itching, prickling and small bumps. The common itchy form is called miliaria rubra. Clear blisters near the surface belong to a different form, miliaria crystallina, which has no inflammation. An absence of itching therefore does not rule out heat rash.134

How can you calm the itching?

1. 1Move somewhere cooler, ideally an air conditioned room, and remove clothing covering the rash.
2. 2Gently wash with cool or lukewarm water, then pat dry without scrubbing. Remove wet clothing.
3. 3Apply a cool damp cloth, or an ice pack wrapped in a towel, for up to 20 minutes.
4. 4Leave the area uncovered where practical, or wear clean, loose cotton clothing. Use lightweight bedding and limit activities that make you sweat.
5. 5Tap or pat the rash rather than scratching. Avoid perfumed shower gels and creams.

Cooling and airing the skin are the priorities, which leaves the bathroom shelf with surprisingly little to contribute. Avoid thick ointments and products that block sweat from escaping. If itching is intense, ask a pharmacist about calamine lotion, antihistamine tablets or hydrocortisone cream before choosing a treatment. Children under 10 need advice from a doctor before using hydrocortisone. Calamine can dry the skin; ask about suitable care if that happens.1234

How long should heat rash last?

Most cases settle within a day or two after moving to a cooler environment, although clearing can take a few days. Scratching can delay healing and break the skin, allowing infection. Get medical advice if the rash is not improving after a few days, or if a child keeps getting heat rash. Contact a doctor if your baby has a rash and you are worried.124

Could an itchy rash be something else?

Itching alone cannot identify heat rash. Contact dermatitis, a reaction to an irritant or allergen, can also cause intense itching, burning, swelling and blisters. A rash where you applied a fragranced product is a reason to consider that possibility. Tell a clinician about new soaps, lotions, cosmetics or household products, and whether cooling has helped.56

When should you get medical help?

Seek medical advice for severe or unexplained itching, significant pain, fever, chills, or skin around the rash that becomes warm or swollen. Yellow or green fluid and red streaks are also signs of infection. Seek immediate medical attention for a sudden rash that spreads quickly, trouble breathing or facial swelling.167