Neonatal dermatology

Neonatal erythroderma ( Fig. 4.3.1 )

Erythroderma in the neonatal period (defined as erythema affecting >90% of the body surface area) has many causes, some of which may be life threatening. Admission is required for investigation, diagnosis and management. Erythrodermic infants are at risk of temperature instability, fluid loss and infection due to abnormal skin barrier function.

Infantile seborrheic dermatitis/eczema

Eczema usually presents later in infancy, although it can present in the neonatal period. This presentation has been described as infantile seborrheic dermatitis in the past, but international opinion is divided as to whether seborrheic dermatitis is a subset of eczema or a separate entity. It may commence on the scalp and face as confluent erythema and vesicles with adherent yellow-brown scale, or within the nappy area where it results in moist erythema in the inguinal folds. The scale on the scalp can become quite thick and adherent, so-called cradle cap. In the flexures of the neck, axilla, antecubital and popliteal fossae there may be a confluent moist erythema. On the trunk there may be oval erythematous scaly lesions which may coalesce.

Treat with soap-free emollient washes and regular application of moisturiser. Topical antifungals (e.g. miconazole), and 1% hydrocortisone, can be effective if needed. Scale can be lifted from the scalp by massaging with a nonirritating oil or moisturiser and use of 2% ketoconazole shampoo. No feeding changes are needed.

Any neonate presenting with significant and widespread eczema should be assessed for conditions including ichthyoses, Netherton syndrome and other causes of erythroderma (see Chapter 15.1 , Dermatology).

Psoriasis

Psoriasis is uncommon in the neonatal period and usually presents as anogenital erythema. Pustular psoriasis can cause sheets of exfoliative erythema with sterile pustules (see Chapter 15.1 , Dermatology).

Ichthyosis

Neonates with more severe forms of ichthyosis may present to EDs with complications of dehydration (due to increased transepidermal water loss), infection or failure to thrive (see Chapter 15.1 , Dermatology).

Neonatal lupus erythematosus ( Fig. 4.3.2 )

Neonatal lupus erythematosus occurs in infants whose mothers are positive for anti-Ro/SSA and/or anti-La/SSB antibodies. Most of these mothers are asymptomatic and unaware of their antibody status. About 2% of infants of antibody-positive mothers develop complete heart block and 4–16% develop cutaneous neonatal lupus.

Skin lesions in neonatal lupus can first appear from a few days to a few months after birth. Widespread, erythematous, often annular and atrophic lesions develop most often in the periorbital area and scalp but can affect elsewhere. These can be misdiagnosed as tinea or eczema. They persist for months before clearing as the maternal antibodies clear. Moderate-potency topical steroid assists clearing. Sunlight and ultraviolet light can precipitate or worsen the rash.

The other major manifestation of neonatal lupus is complete heart block (from the third trimester). This is permanent and can be fatal; a pacemaker is required. Only a small proportion of infants with neonatal lupus have both cardiac and cutaneous disease.

All infants with neonatal lupus presenting with skin lesions require ongoing follow-up as they appear to have an increased risk of developing autoimmune thyroid or rheumatological disorders during childhood. Approximately 25% of the mother’s subsequent pregnancies develop neonatal lupus and so antenatal care should include cardiac monitoring of the foetus. Any older siblings should be assessed to exclude heart block. Most mothers eventually develop rheumatological disease and also require referral for follow-up.

Zinc deficiency/acrodermatitis enteropathica

Zinc deficiency, either inherited or acquired, can cause a progressive red scaly and crusted rash on the face, distal limbs and perianal region. Onset is usually later in infancy, although it can rarely be in the neonatal period (see Chapter 15.1 , Dermatology).

Langerhans cell histiocytosis (see Chapter 15.1 , Dermatology)

Langerhans cell histiocystosis (LCH) is a rare histiocytic disorder that can present at any age but is most common between one and three years of age. LCH may present in several ways especially as a petechial nappy rash or seborrheic dermatitis. It should be considered as a possible diagnosis in any unusual, non-healing rash in infancy.

Tinea corporis

This is extremely uncommon in the neonatal period. Red annular rashes in neonates are more likely to be eczema, urticaria or neonatal lupus.

Congenital syphilis

Congenital syphilis is due to the transmission of Treponema pallidum from an infected pregnant woman to her foetus. The severity of disease is variable; as many as 90% of affected newborns have no signs at birth. Clinical findings include hepatomegaly, jaundice, nasal discharge, lymphadenopathy, pseudoparalysis and ophthalmological/central nervous system (CNS) and skeletal changes. The rash usually appears 1 to 2 weeks after the rhinitis and consists of red-pink spots most prominently on the back, buttocks, palms and soles. It progressively desquamates and fades to a dull red/copper colour. Occasionally, congenital syphilis can present with bullae, periorificial fissuring or condylomata lata (moist perineal papules).

The diagnosis can be made by assessment of maternal and infant serology, darkfield examination of infected body fluids or histology of the placenta/umbilical cord or infected tissue with immunofluorescence. X-rays may show evidence of bony changes in long-standing disease.

Referral to a paediatric infectious disease specialist for management is appropriate. Child-protection issues need to be considered if acquired postnatally.

Herpes simplex

Neonates who acquire herpes simplex virus (HSV) at birth usually present at a few days of age with grouped vesicles, often on the scalp. Lesions may rapidly spread and coalesce. Herpes infection may be associated with fever, pneumonitis, transaminitis and conjunctivitis. Approximately 30% of neonates with apparently localised skin disease also have CNS involvement.

In addition to viral testing of the vesicle as above, blood should be taken for blood count and liver function, and blood and cerebrospinal fluid HSV PCR should be performed. Admission and empiric treatment with intravenous aciclovir are essential until HSV has been excluded.