Neonatal dermatology – the benign conditions

Neonates have rashes of all shapes and sizes. It’s important for us to be able to reassure parents where appropriate. This two part series deals with neonatal dermatology. In Part 1, we look at the benign conditions, and in Part 2 we will look at the more sinister ones.

In all the following skin conditions, the baby is systemically well. If the baby is not well, the rash is just an incidental finding or your diagnosis is incorrect.

Erythema toxicum

• —There are usually central papules or pustules surrounded by areas of erythema
• —Absence of mucosal, palmar and plantar involvement
• —Benign, self-limiting, asymptomatic disorder of unknown etiology
• —Occurs in up to 50% of term infants; 5% preterm infants
• —Presents at 24-48 hours of life, fades within 5-14 days, but recurrences may occur for several weeks
• —Smear (Tzanck smear) of pustule reveals eosinophils

Transient neonatal pustular melanosis

• —Self-limiting dermatosis of unknown etiology
• —Occurs more frequently in black males
• —Usually presents at birth
• —Pustule on non-erythematous base, crusts over several days, which ruptures and leaves a hyperpigmented macule with collarette of fine scale
• —Hyperpigmentation fades in 3 weeks to 3 months
• —Smear of pustule reveals neutrophils

Mongolian spot

• —Flat, slate-gray to bluish-black, poorly circumscribed macules/patches
• —Most commonly located over the lumbosacral area and buttocks
• —Common in black, asian, and hispanic infants
• —Usually fade by 7 years of age

Cutis marmorata

• —Transient, net-like (reticular), reddish-blue mottling
• —Caused by variable vascular constriction and dilation
• —Response to chilling, resolves with warming
• —Benign in neonates and usually subsides by 6 months, but may persist longer in very fair skinned individuals
• —If persists past 6 months, may be a marker for hypothyroidism

Congenital nevomelanocytic nevi

• —Pigmented macules or plaques with dense hair growth
• —Giant CNN (>2% of TBS) are associated with a 2-10% lifetime risk of melanoma
• —Highest risk of malignant change occurs in first 3-15 years of life
• —Early treatment with full-thickness excision followed by grafting if possible, otherwise close observation
• —Small to medium sized CNNs are also associated with a higher risk of malignant change than acquired moles, but incidence is unknown

Acrocyanosis

• —Hands and feet become variably and symmetrically blue
• —Resolves with warming of the skin
• —Recurrence unusual after one month of age

Haemangioma

• —Congenital vascular malformation
• —Occur in 10% of all newborns
• —Presents in first few months of life
• —Caused by dilated capillaries occupying the dermal and subdermal layers with endothelial proliferation.
• —Rapid growth for the first 6-12 months, then a plateau period, then slow involution
• —50% involute by age 5, 90% by age 9

—Refer to dermatology if lesion involves a vital structure or if there are multiple lesions

Salmon patch/stork bite

• —Vascular malformation;
• —Seen in 60% of infants
• —“Stork bite” macular pink areas of distended capillaries found on the nape of the neck, upper eyelids, nose, or the upper lip.
• —They have diffuse borders, blanch with pressure, and become pinker with crying.
• —Fades in first year of life

Port wine stain

• —Purplish-red vascular malformation present at birth
• —Lesions do not enlarge but remain flat and persist
• —When port wine stain involves ophthalmic branch of the fifth cranial (trigeminal) nerve, it can be associated be a constellation termed Sturge-Weber syndrome
• —Sturge-Weber syndrome involves seizures, mental retardation, hemiplegia, and glaucoma

Neonatal acne

• —Develops in up to 20% of newborns (forehead and cheeks)
• —Maternal and endogenous androgen; possible involvement of Malassezia species (controversial) thought to play a role in the pathogenesis, but exact aetiology unknown
• —Lesions involute within 1-3 months, treatment usually unnecessary – does not scar

Milia

• —Pearly yellow papules usually on the face (1-2 days after delivery)
• —Small, white pearly globules. May be 1-2mm in size
• —Usually present on the cheeks, chin, forehead or scalp
• —Larger single milia may occur in the region of the foreskin, scrotum or labia majora
• —Occur in 50% of newborns
• —Common, benign, keratin filled cysts
• —Usually resolve in the 1st month of life

Epstein pearls

• —Oral counterpart of facial milia. Can be seen on the midline of palate or on the alveolar ridges
• —Occurs in approx 60% of neonates
• —No treatment needed

Miliaria

• —Results from obstruction to the flow of sweat and rupture of the eccrine sweat gland
• —Miliaria crystallina – superficial 1-2mm vesicles on non-inflamed skin- stratum coeneum
• —Miliaria rubra (heat rash) – small red papules and pustules. Pruritic-intra epidermal
• —Occur in response to thermal stress
• —Usually erupt in crops in the intertriginous areas, scalp, face, and trunk