SynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyReferences

Information for Patients

View all Images (9)

Miliaria rubra in Infant/Neonate
Other Resources UpToDate PubMed

Miliaria rubra in Infant/Neonate

Contributors: Craig N. Burkhart MD, Dean Morrell MD, Susan Burgin MD
Other Resources UpToDate PubMed


Miliaria rubra, also known as prickly heat or heat rash, is the most common form of miliaria. Miliaria rubra is due to the obstruction of the intraepidermal eccrine sweat ducts. The resultant sweat retention and the escape of sweat into the dermis evokes an inflammatory response that manifests as papules. The predisposing factors are hot and humid conditions, febrile illnesses, and occlusive clothing, dressing, or ointments (eg, Aquaphor).

Miliaria rubra has been reported to occur in newborns with type 1 pseudohypoaldosteronism. This typically resolves upon stabilization of disease.

Other miliaria variants include the most superficial type, miliaria crystallina, as well as those involving deeper occlusion, miliaria pustulosa and miliaria profunda (skin-colored papules with possible associated hypohidrosis or anhidrosis).


L74.0 – Miliaria rubra

72658003 – Miliaria rubra

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

  • Miliaria rubra is often mistaken for a drug eruption, especially after a new antibiotic is started in a febrile patient.
  • Other miliaria variants – Miliaria crystallina, miliaria pustulosa, miliaria profunda.
  • Candidiasis – Usually affects the warm, moist areas, such as groin, axillae, and neck. The lesion consists of beefy red, moist erythema with satellite pustules. A KOH scraping from the pustules demonstrates pseudohyphae and spores.
  • Scabies – Pruritic papules, papulovesicles, nodules, and linear burrows on the palms, soles, wrists, ankles, axillae, groin, and genitals. Unlike miliaria, often involves acral sites, especially the presence of burrows in the finger webs. Family history is often present.
  • Varicella presents as vesicles on an erythematous base ("dewdrops on a rose petal") and are in different stages of development.
  • Folliculitis – Has follicular-based pustules.
  • Neonatal or infantile acne – Can also be worsened by occlusion but usually lacks pruritus and is less acute.
  • Herpes simplex virus (HSV) infection – Characteristic grouped vesicles on an erythematous base.

Best Tests

Subscription Required

Management Pearls

Subscription Required


Subscription Required


Subscription Required

Last Reviewed:03/19/2017
Last Updated:04/28/2019
Copyright © 2023 VisualDx®. All rights reserved.
Patient Information for Miliaria rubra in Infant/Neonate
Print E-Mail Images (9)
Contributors: Medical staff writer


Miliaria rubra, also known as heat rash or prickly heat, is a common skin condition caused by the blockage of the sweat gland. Although this rash can be caused by fever, heat rash is more commonly seen in infants who are dressed too warmly (in the winter).

Who’s At Risk

Heat rash is common in over-bundled infants in the winter and those who have recently moved to a hot and humid climate.

Signs & Symptoms

There are 2 forms of heat rash: miliaria crystallina, which consists of tiny clear fluid-filled blisters that pop and leave behind some scale; and miliaria rubra, which has similar clear fluid-filled blisters, but they are surrounded by red areas or tiny red bumps.

In infants, lesions of miliaria crystallina tend to occur on the head, neck, and upper part of the trunk. Miliaria rubra tends to occur on the neck and in the groin and armpits.

Self-Care Guidelines

Prevention and treatment of heat rash consist of controlling heat and humidity. Acetaminophen or ibuprofen can help to reduce fever. Remove any occlusive clothing, limit activity, and seek air conditioning or any cooler environment. Cool compresses can also help with the discomfort. Most infants recover uneventfully within a matter of weeks. Young infants should not be given fluids other than breast-milk or formula unless instructed by the child's doctor.

When to Seek Medical Care

The most common complications of heat rash include secondary infection from scratching and heat exhaustion.

Call your child's doctor if he/she is scratching significantly. There are medications that can help relieve the itching and, thus, prevent infection. Infected areas may need antibiotics. Call your child's doctor if the area develops pus, redness, crusting, swelling, or tenderness.

In cases of heat exhaustion, the skin will appear hot and flushed without any sweat. Your child may complain of dizziness, nausea, weakness, headache, confusion, or difficulty breathing. This can progress to heat stroke, so medical care should be obtained right away. Symptoms of heat stroke include a very high temperature, of 105°F or greater, decreased or loss of consciousness, or seizure.

Heat intolerance is recognized by a lack of sweating of the affected skin, irritable behavior, and a change in alertness. Call for emergency medical help if your infant shows one or more of the following symptoms:
  • Your baby is sweaty and restless, then suddenly lethargic and sleepy. If your baby is awake, he or she may seem sort of "glazed" and limp or go from flushed to pale.
  • Your baby shows signs of dehydration: a dry mouth, no tears with crying, cracked lips, sunken eyes, or has less than 1 wet diaper every 6-8 hours.
  • A decreased desire or ability to feed.
  • Vomiting.
  • Seizure.
  • It feels like he or she has a fever.
If you notice some combination of these signs, do everything you can to cool your baby off and have him or her seen by a doctor right away.
  • Get your child into the shade or into an air-conditioned space.
  • Undress your child and apply cool compresses.
  • Do not give fluids.


If there are signs of bacterial skin infection related to the heat rash or otherwise, oral or topical antibiotics may be given.

Dehydration may be treated with intravenous fluids, especially if there is vomiting. Heat stroke is treated by trying to quickly reduce the core temperature to normal. Immersion, evaporative, or invasive cooling techniques may be used in addition to rapid administration of intravenous fluids.


Bolognia, Jean L., ed. Dermatology, pp. 510, 578-579. New York: Mosby, 2003.

Wolff, Klaus, ed. Fitzpatrick's Dermatology in General Medicine. 7th ed., p. 730. New York: McGraw-Hill, 2008.
Copyright © 2023 VisualDx®. All rights reserved.
Miliaria rubra in Infant/Neonate
A medical illustration showing key findings of Miliaria rubra : Fever, Rash, Developed rapidly , Pruritus
Clinical image of Miliaria rubra - imageId=2037503. Click to open in gallery.
Copyright © 2023 VisualDx®. All rights reserved.