Miliaria

Miliaria is an itchy, papular, and sometimes vesicular, eruption on the trunk caused by obstruction of sweat glands. Presentation varies depending on the location of the obstruction.

Miliaria crystallina is caused by obstruction in the stratum corneum, and commonly accompanies fever and profuse sweating.

Miliaria rubra (also known as ‘prickly heat’) is caused by intra-epidermal obstruction, and occurs in hot and humid climates—some people (eg infants) are more susceptible than others. Staphylococcal folliculitis may complicate this condition.

Miliaria profunda is caused by obstruction and rupture of the sweat duct at the dermo-epidermal junction, and can follow repeated episodes of miliaria rubra.

Management of miliaria involves preventing sweating and occlusion. Remove plastic mattresses or mattress protectors on beds, and use cotton sheets and a sheepskin underlay. Wear light breathable clothing and use air conditioning. Calamine lotion may provide relief, and in severe cases, mild topical corticosteroids (eg hydrocortisone 1%) can relieve symptoms.

If the patient continues to sweat, the condition is likely to recur for a few days at a time over several months until the patient becomes acclimatised.