• Dermatology
• Paediatrics

A 16-month-old boy presented with autoimmune haemolytic anaemia, thrombocytopenia and rashes. His older brother died at 8 months of age from meningitis. Their parents were non-consanguineous. He had a chest infection at 3 months of age, recurrent eczema from 6 months of age and pallor from 9 months of age. Examination revealed hepatosplenomegaly and generalised eczema plaques. Next-generation sequencing for a primary immunodeficiency identified a novel hemizygous missense variant in the WAS gene, c.219C>G (p.Cys73Trp). WAS protein expression was absent in his lymphocytes on flow cytometry, confirming the diagnosis of Wiskott-Aldrich syndrome, an X linked recessive inborn error of immunity.1

He developed umbilicated papules which evolved into ulcerated, haemorrhagic papules and bullae resembling molluscum or mpox lesions (figure 1).2 Skin biopsy showed viral cytopathic changes (figure 2). PCR and electron microscopy findings for orthopox viruses were negative. Cytomegalovirus (CMV) PCR was detected from the contemporaneous swab of the skin biopsy site. Dermal lymphocytes showed positive nuclear staining for the CMV immunohistochemical stain (figure 3). Viral serologies returned negative except for a CMV-DNA viral load of 19 000 IU/mL. The rashes resolved following treatment with CMV immunoglobulin and 3 weeks of oral valganciclovir. There was no other organ involvement.

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Figure 1

Umbilicated and haemorrhagic papules and bullae on limbs and trunk.

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Figure 2

Histology of skin biopsy H&E 40 ×: Extensive epidermal necrosis with balloon degeneration of keratinocytes.

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Figure 3

Skin biopsy: Positive cytomegalovirus stain.

The clinical presentation of cutaneous CMV infection is non-specific including macules, papules, urticaria, scarlatiniform eruptions, plaques or oral and perianal ulcers.3 4 Severe cases can be treated with intravenous ganciclovir or foscarnet.5

This case highlights the importance of recognising atypical rashes in immunocompromised patients, such as an extensive pox-like eruption in this case. These patients should undergo thorough investigations such as an immunology and infectious diseases workup for timely treatment.