Erythema toxicum neonatorum
Occurs in 30-70% of full-term infants, making it the most common pustular eruption in newborns. Etiology is unknown. This rash is characterized by multiple yellow or white erythematous macules and papules (1-3mm in diameter) which can rapidly progress to pustules on an erythematous base (often described as a “flea-bitten” appearance). The lesions are distributed over the trunk and proximal extremities, but spare the palms and soles. They may be present at birth, but usually appear within 24-48 hours. The rash will typically resolve in 5-7 days, but may last several weeks. Diagnosis is typically clinical, but can be confirmed by microscopic evaluation, which demonstrates numerous eosinophils. No treatment is needed.
Transient neonatal pustular melanosis
Mostly affects full-term African American infants (4.4%, vs. 0.2% Caucasian infants). Consists of three types of lesions: 1) small pustules on a non-erythematous base, usually present at birth; 2) erythematous macules with a surrounding collarete of scale; 3) hyperpigmented macules that gradually fade over several weeks to months. The vast majority of lesions lack surrounding erythema, in contrast with erythema toxicum neonatorum. These lesions rupture very easily, and may affect all areas of the body (including palms and soles). Lesions are typically present at birth, and usually resolve spontaneously within 3 months. This is usually diagnosed clinically, but if examined microscopically will show numerous neutrophils.
Neonatal cephalic pustulosis ("neonatal acne")
Occurs in approximately 20% of infants and does not appear to run in families. The cause is not known: some theories are that it is caused by the stimulation of sebaceous glands by maternal and endogenous androgens, or that it is an inflammatory reaction to skin colonization with Malassezia species. The mean onset of this is 3 weeks of age. It is characterized by inflammatory papules and pustules, typically with no comedonal lesions, and a distribution limited to the face (particularly pronounced on the cheeks), and sometimes to the scalp. This is typically mild and can be treated with daily cleansing with soap and water and avoidance of oils and lotions. No additional treatment is typically needed, although 2% ketoconazole cream BID, 2.5% benzoyl peroxide lotion, or 1% hydrocortisone cream QD have been shown to expedite the clearance of lesions.
Distinct from neonatal acne, this presents typically at 3-4 months of age. It is a result of hyperplasia of the sebaceous glands secondary to androgenic stimulation, and is more common in infant boys. The clinical presentation of infantile acne is typically more severe than that of neonatal acne and consists of typical acneiform lesions including inflammatory papules, comedones, pustules, with occasional nodules in the face. The typical clinical course is for lesions to clear spontaneously by late in the first year of life, but this can persist until 3 years of age. Treatment is sometimes required, because these lesions can persist and can cause permanent scarring, unlike neonatal acne. When there is mild or moderate inflammation, treatment can be made with mild keratolytic agents, such as benzoyl peroxide 2.5%, topical antibiotics (e.g. clindamycin or erythromycin), or topical steroids. In severe cases, systemic antibiotic therapy or oral isotretinoin can be used.
a benign vesiculopustular condition with an often more chronic course than other benign neonatal lesions. The etiology is unknown. This is characterized by recurrent crops of intensely pruritic vesiculopustules, mainly on the palms and soles, but sometimes on the extremities. These can be present at birth or have onset any time during the first year of life. Recurrences can occur every 2-4 weeks and can last 5-10 days. Diagnosis is typically clinical. These lesions typically resolve within 2 years. There is very little data regarding the efficacy of various treatment modalities. Case series have shown some efficacy of treatment with topical corticosteroids, oral antihistamines, oral erythromycin, and oral dapsone.
Milia are 1-2mm whitish yellow papules that are found on the nose, cheeks, chin, and forehead. These typically resolve in the first few weeks of life. They are secondary to the retention of keratin and sebaceous material in the pilacious follicles. These lesions disappear spontaneously, most frequently within the first month of life.
a very common finding in newborns, particularly in warm climates, and is caused by accumulation of sweat beneath the eccrine sweat ducts which are obstructed by keratin. It affects up to 40% of infants, and usually occurs within the first month of life. There are several different types of lesions that are characteristic: 1) miliaria rubra (“heat rash” or “prickly heat”) occurs when the obstructed sweat leaks into the dermis and causes a localized inflammatory response, resulting in small groups of erythematous papules and pustules; 2) miliaria crystalline is characterized by small thin-walled vesicles resembling dewdrops without inflammation; 3) miliaria pustulosa results from localized inflammation, and consists of pustules with an erythematous base; 4) miliaria profunda has lesions that are skin colored papules and pustules. Miliaria is rarely present at birth; it usually presents during the first week of life, especially in association with the warming of the infant by clothing or an incubator. Lesions are typically distributed on the face and scalp, as well as intertriginous area. No specific treatment is typically needed, and lesions typically resolve when the infant is placed in a cooler environment and occlusion is avoided. Mild topical corticosteroids can be used for refractory lesions.
a diagnosis of exclusion, these are oval, thick-walled vesicles or bullae that are filled with sterile fluid. Lesions may have erosion or crusting present. These may be unilateral or bilateral and are usually located on the dorsal aspect of the wrists, hands, or fingers of neonates who are noted to suck excessively at the involved regions. Treatment is often not needed, but sometimes topical antibiotic ointments can be used.
symmetric, reticular mottling of the skin of the extremities and trunk. Caused by vascular response to cold, and typically resolves with warming. No treatment is needed.
Harlequin color change
observed when an infant is lying on his or her side, and characterized by intense reddening of the dependent side and blanching of the non-dependent side, with a demarcation line along the midline. Duration ranges from seconds to 20 minutes. Lesions resolve with increased muscle activity or crying. This affects roughly 10 percent of newborns, and is entirely benign. The etiology of this is unknown.
Slate-Greay Macules (previously know as mongolian spots)
The most frequently encountered pigmented lesions in newborns, these are very common in Asian, African American, and Hispanic neonates, while they are very uncommon in Caucasian neonates. These are characterized by congenital blue-grey pigmented macules with undefined borders. The diameter can be 10cm or more, and lesions are most commonly found in the sacro-gluteal region, or in the shoulders. These are completely benign lesions and usually fade during the first or second year of life.
Bronze baby syndrome
Refers to diffuse gray-brown discoloration of the skin that can develop in infants 1-7 days after initiation of phototherapy for hyperbilirubinemia. The condition gradually resolves without sequelae within several weeks after discontinuation of therapy.
An extremely common rash characterized by erythema and greasy scales, which usually occurs on the scalp (“cradle cap”), but can also occur on the face, ears, neck, and in the diaper area. The exact etiology is not known. In infants, this usually resolves spontaneously within weeks to months. Treatment has not been extensively studied, but can include topical antifungals, corticosteroids, and selenium sulfide. Treatment typically begins with frequent shampooing and removal of the scales with a soft brush, as well as application of an emollient (e.g. mineral oil) to loosen the scales. If dermatitis persists, therapy can be escalated to topical corticosteroids, antifungals, keratolytics, or antiproliferative agents.
Nevus sebaceous of Jadassohn
This is a congenital lesion that occurs primarily on the scalp and face. It is usually present at birth, but can appear later. The lesion is typically a solitary, well-circumscribed, oval or linear waxy plaque that is yellow to tan in color. Size can be from a few millimeters to several centimeters. The lesions will increase in size proportionate to the growth of the child. Secondary neoplasms, both benign and malignant, can occur within these lesions, although their development is very uncommon. Treatment of choice is surgical excision because of the possibility for development of secondary neoplasms within the lesions. However, because the risk is low, some recommend clinical follow-up of the lesion.
Aplasia cutis contenita
This is a group of heterogeneous diseases that is characterized by congenital focal absence of skin. It is most often limited to a solitary midline posterior scalp lesion.
- UpToDate. Benign skin and scalp lesions in the newborn and young infant. Dynamed. Newborn checkup.
- O’Connor N et al. Newborn Skin: Part I. Common Rashes. American Family Physician 2008 Jan; 77(1): 47-52.
- Dermatlas. http://dermatlas.med.jhmi.edu/derm/