Heat rash in infants: what parents should know

Heat rash, also called prickly heat or miliaria, develops when sweat ducts become blocked. Babies can be more prone to it because their skin and temperature control are still developing. Look for clusters of tiny red or clear bumps, mild redness, or prickling in neck folds, the upper chest, back, or covered areas. Explore related information about [Skin Bumps](/symptoms/skin-bumps/) and [Skin Redness](/symptoms/skin-redness/). The rash itself is not contagious, but a similar-looking eruption can have another cause.

Move the infant to a cooler, well-ventilated space and remove an extra layer. Dress them in loose, breathable clothing. Bathe with lukewarm water if needed, then pat the skin dry, especially inside folds. Avoid thick oils, greasy ointments, fragranced products, and vigorous rubbing because they can hold in heat or irritate delicate skin. Do not use a medicated cream on an infant’s skin unless a clinician has advised it; [Emollient Therapy](/treatments/medical-dermatology/emollient-therapy/) or [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/) may not suit every rash or body area.

Contact a clinician if the rash spreads, becomes painful, develops blisters, crusting, pus, or marked swelling, or does not begin settling after cooling measures. Seek urgent help if the infant is difficult to wake, has trouble breathing, is feeding poorly, has fewer wet nappies, or feels unusually hot. Fever in a young infant deserves prompt medical advice. A clinician can distinguish heat rash from infection, eczema, or another [Skin Rash](/symptoms/skin-rash/).

Ask whether the appearance and location fit heat rash, whether any product should be stopped, and how to protect the affected folds while they heal. Mention recent fever, reduced feeding, new detergents, and how quickly the spots appeared.