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A rash that appears due to humidity and clothing may be heat rash. Heat rash is prevalent during the hot summer months and is caused by blocked sweat ducts and trapped perspiration. Heat rash symptoms may also include itchy skin, painful red bumps as well as lack of sweating in the affected area. Seek medical care if you experience fever, increased pain or pus drainage from the red bumps.


Heat rash occurs whenever sweat ducts become blocked and perspiration gets trapped, whether due to clothing, sunscreen, lotions and other topical ointments and creams. It may also occur as a result of skin rubbing against skin or clothing as well. Common areas where heat rash occur include between the legs, near the groin area, under the arms as well as anywhere else friction occurs. Heat rash is more prevalent during the hot summer months or in tropical climates. It also occurs as a result of intense physical activity.

Signs and Symptoms

Depending on the severity and location of the outbreak, signs and symptoms of heat rash include red skin and small blister-like bumps that pop easily and cause no pain. Repeated or prolonged heat rash may affect deeper layers of the skin and may cause the affected area to become itchy and raw as well as develop into flesh-colored bumps. Other signs and symptoms may include painful blisters and bumps as well as a lack of sweat at the affected area.


To prevent blocked sweat ducts, stay in a cool, air-conditioned environment whenever possible. Wear loose-fitting clothing that either wick away sweat or are made out of breathable materials such as cotton. Never wear brand new workout clothes without washing them first, as it may contain chemicals and residue that may irritate skin. Use a lubrication cream to prevent chafing. Take a shower after any intense physical activity and use a loofah or washcloth to scrub away dead skin, dirt and other sweat duct-blocking irritants.

Other Considerations

Heat rash usually goes away on its own within a week to 10 days. To treat the symptoms of heat rash like itchy skin, use a cool, damp compress or topical ointments such as calamine lotion. Seek medical care if you experience difficulty breathing, lack of sweat, swollen lymph nodes, fever or a rapid pulse, as these may be symptoms of a more serious condition such as heat exhaustion or stroke.