DETERIORATING ECZEMA
History
George is a 2-year-old boy who presents to the paediatric rapid referral clinic with a worsening of his eczema. The latter was diagnosed by the GP when he was 6 months old. He has been treated with a variety of emollients and topical steroids which are applied on an intermittent, as-required basis. The parents report that over the last 3 days the eczema has gradually deteriorated and also become more itchy. George also has asthma which is treated with inhaled budesonide twice a day and inhaled salbutamol on an as-required basis. His mother had eczema as a child but grew out of it and his father has hay fever.
Examination
George is well hydrated. His temperature is 38.3C, he is itchy and miserable. He has widespread eczema all over his body, which is worst on his face, hands and arms where the skin feels moist (see Fig. 46.1). A number of vesicles and some punched-out lesions can be seen on the face, hands and arms. There are also pustules and some areas of honey-coloured crusting in those areas. In some areas the lesions have coalesced. The marked scratching that has taken place makes the exact nature of the lesions more difficult to determine. His eyes are puffy and there are some surrounding lesions. The eyes themselves appear normal but are difficult to assess fully. There is cervical, axillary and inguinal lymphadenopathy. His chest is clear.
Figure 46.1 Eczema on George’s face. (Reproduced with kind permission from Kane KSM et al., Color Atlas and Synopsis of Pediatric Dermatology, McGraw Hill, 2002.)
INVESTIGATIONS
Normal
Haemoglobin 10.2 g/dL 10.5–14.0 g/dL
White cell count (WCC) 23.2 109/L 5.0–15.0 109/L
Neutrophils 9.2 109/L 1.5–8.0 109/L
Lymphocytes 14.0 109/L 4.0–10.0 109/L
Platelets 392 109/L 150–400 109/L
Urea and electrolytes Normal
C-reactive protein (CRP) 116 mg/L 6 mg/L
Questions
• What further investigations are important?
• What is the diagnosis?
• What is the treatment?
Medicine
A blood culture should have been done at the same time as the other blood tests, as there is a small possibility that he may have a septicaemia. Skin swabs should be taken for bacteriology and virology (virology swabs require special viral medium). The diagnosis is eczema herpeticum with superadded bacterial infection. It would be worth asking if the child has had similar previous episodes or if anyone in the family has herpetic cold sores. Eczema herpeticum is caused by herpes simplex virus infection of eczematous skin. The infection spreads along the skin and haematogenously. Vesicles and pustules occur and these may coalesce, erode the skin and become haemorrhagic and crusted. The lesions can disseminate rapidly and may cause life-threatening infection. Eczema herpeticum may also affect the conjunctiva and cornea and can cause a keratitis that, if left untreated, may lead to blindness. The diagnosis is sometimes made when a patient fails to respond to antibacterial therapy. The raised temperature, WCC and CRP indicate that the infection is severe, and the lymphocytosis is suggestive of a viral infection. The diagnosis can be made by microscopy, culture or viral PCR. Bacterial infection can also lead to an acute deterioration in eczema (and is more common than herpetic infection). The pathogen is usually Staphylococcus aureus and occasionally Streptococcus. Staphylococcal infection can lead to honey-coloured crusting, as in this case. In our case, the secondary bacterial infection is most likely to be due to scratching, leading to the Staphylococcus that often colonizes the skin, causing infection. In some cases it can be difficult to determine if the eczema has been infected by bacteria or viruses and both need to be treated. The lymphadenopathy is secondary to the infected eczema. In some cases of widespread infected eczema, there can be marked fluid loss from the skin, which may be exacerbated in the presence of a temperature. In this case the patient is well hydrated, but hydration should be carefully monitored (the situation is somewhat analogous to fluid loss in a burn). Intravenous acyclovir should be administered. If there is any concern about possible eye involvement, as in this case, an urgent ophthalmic opinion should be sought. In addition, intravenous antibiotics (e.g. co-amoxiclav) should be given because of the superadded bacterial skin infection and possible septicaemia. Analgesics, antipyretics and anti-pruritic agents, i.e. antihistamines, should be prescribed. Topical treatment with steroids and other immunosuppressants (e.g. tacrolimus) should be discontinued (this is in contrast to bacterial infections alone when steroid creams are usually continued alongside the antibiotic). Topical treatments can usually be restarted after 1 week when the patient has improved.
KEY POINTS
• Herpetic infection can lead to severe worsening of eczema (eczema herpeticum).
• Bacterial infection is the commonest cause for an acute deterioration in eczema, with the commonest pathogen being Staphylococcus aureus.
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