Erythema toxicum. The most common newborn rash, it consists of erythematous macules with a central papule or pustule. It can be present at birth, typically appears within the first 48 hours, and may appear at up to 2 weeks of age. It is more common in full-term infants and more common on the trunk, extremities, and perineum. New lesions can appear after the initial onset and usually disappear after a week (Plate 4).
Transient neonatal pustular melanosis. These 2- to 5-mm pustules are usually present at birth on various sites, typically the face and sacrum of full-term infants. Pustules evolve and disappear within 48 hours, but can leave hyperpigmented macules that eventually resolve but may persist for months (Plate 5).
Sebaceous gland hyperplasia. Tiny yellow papules usually occurring on the cheeks and nose. Smaller and more yellow than milia.
Milia. Tiny (1-mm) white-yellow papules frequently present on the face, chin, and forehead and scalp. Caused by sebaceous retention cysts (Plate 6).
Miliaria crystallina. Obstruction of eccrine/sweat ducts. May appear on the scalp or face as vesicular or papular lesions with or without erythema. Exacerbated by heat and humidity, they resolve quickly when the infant is cooled.
Miliaria rubra (“prickly heat”). One- to two-millimeter papules or papulopustules surrounded by small red areas. Miliaria pustulosis is a variant with more pustules and less erythema.
Miliaria profunda. Deep obstruction of the sweat ducts. White papules and edema that can prevent sweating, leading to hyperthermia.
Acropustulosis of infancy. Recurrent areas of pruritic vesicopustules develop on the palmar surface of the hand and plantar surface of the feet. Usually last 7–14 days (Plate 7).
Seborrheic dermatitis. Patchy redness and scales on the scalp (“cradle cap”), face, skin folds, and behind the ears.
Neonatal acne. Erythematous comedones, papules, and pustules. May be present at birth or develop during early infancy; may take several weeks/months for complete resolution (Plate 8).
Sucking blister. Vesicular or bullous lesions present at birth on fingers, lips, or hands; no associated erythema (distinguishes these from herpetic lesions).
Subcutaneous fat necrosis. Erythematous nodules and plaques occurring during the first few weeks of life and resolving by 2 months of age. Usually on areas of trauma (face, back, arms, legs, and buttocks). Hypercalcemia can occur if these lesions calcify (Plate 9).
Nevus simplex (“stork bite,” “salmon patch,” “angel's kiss”). Pink macules that are dilated superficial capillaries, seen commonly at the nape of the neck, midforehead, and upper eyelids, but also on nose and upper lip, that usually fade within a year. The most common vascular malformation.
Mongolian spot (dermal melanocytosis). A blue-black macular discoloration at the base of the spine and on the buttocks but can occur elsewhere. More common in blacks (>90%) and Asians (81%); usually fades over several years. Extensive spots have been described in infants with GM1 gangliosidosis (Plate 10).
Harlequin sign (color change, not Harlequin fetus). Secondary to vasomotor instability, there is a sharp demarcation of blanching (one side of the body is red and the other is pale) that usually only lasts a few minutes.
Infantile hemangioma. A common vascular tumor (3–5% of all infants). More common in girls and preterm infants.
Benign petechiae. Nonblanching erythematous macules present on the lower body after a breech delivery or upper body with a vertex presentation.