Erythema toxicum may appear in approximately one half of all normal newborn infants. The condition may appear in the first few hours of life, or it can appear after the first day. The condition can last for several days.

Although erythema toxicum is harmless, it can be of great concern to the new parent. Its cause is unknown, but thought to be related to the immune system.

The main symptom is a rash of small, yellow-to-white-colored bumps (papules) surrounded by red skin. There may be a few or several papules. They are usually on the face and in the middle of the body. They can also be seen on the upper arms and thighs.

The rash can change rapidly, appearing and disappearing in different areas over hours to days.

Your baby's health care provider can often make a diagnosis during a routine exam after birth. Testing is usually not needed. A skin scraping may be done if the diagnosis is not clear.

The large red splotches usually disappear without any treatment or changes in skin care.

The rash usually clears within 2 weeks. It is often completely gone by age 4 months.

Discuss the condition with your baby's provider during a routine examination if you are concerned.

Erythema toxicum neonatorum; ETN; Toxic erythema of the newborn; Flea-bite dermatitis

Calonje E, Brenn T, Lazar AJ, Billings SD. Neutrophilic and eosinophilic dermatoses. In: Calonje E, Brenn T, Lazar AJ, Billings SD, eds. McKee's Pathology of the Skin. 5th ed. Philadelphia, PA: Elsevier; 2020:chap 15.

Younger SB, Martin KL. Dermatologic diseases of the neonate. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 688.

Updated by: Ramin Fathi, MD, FAAD, Director, Phoenix Surgical Dermatology Group, Phoenix, AZ. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.