Red spots on the skin have various causes. For example, exposure to irritants can cause dermatitis, fungal infections can cause ringworm, blood vessels can cause spots called purpura, and some autoimmune disorders can cause rashes.
Some spots will go away on their own, but others may require treatment.
This article discusses 13 causes of red spots on the skin, whether it is a cause for concern, and when to seek immediate medical attention.
Heat rash (Milaria)
Red spots on the skin after exposure to the sun are caused by a condition called “heat rash”. Heat rash (miliaria) occurs when the sweat glands under the skin are blocked. It causes small, red, spiky bumps on the skin that are itchy and painful.
Heat rash usually occurs in folds of the skin or in areas where sweat accumulates, such as the armpits, chest, back, arms, and groin.
People who live in hot climates, sweat a lot, or lie down for long periods of time are more likely to develop heat rash.
Heat rash can be treated at home by taking cool baths, cold compresses, and wearing loose clothing to reduce skin temperature. Also, avoid applying thick moisturizing creams that trap heat on the skin. 3
Heat rash usually goes away on its own after a few days. However, if the skin is damaged, it can cause a secondary infection. In severe cases, oral or topical antibiotics may be needed to relieve pain and clear the infection.
Contact your healthcare provider if you develop signs of infection, such as a heat rash, peeling skin, or purulent discharge.