An important cause of erythroderma

A 78 year old man presented from an assisted living facility with an itchy dermatitis that was refractory to antifungal and topical steroid treatment. Physical examination showed diffuse scaly erythema covering 90% of the body surface area and yellow crust on the hand webspaces (fig 1⇓). Mineral oil preparation showed a dense collection of scabies mites. The pruritic rash cleared within four weeks after treatment with ivermectin 200 µg/kg and permethrin 5% cream for crusted scabies. It is important to consider Norwegian (or crusted) scabies on the differential diagnosis of erythroderma in the elderly in addition to the more common causes, including psoriasis, eczema, and drug reaction. Typical dermatologic signs of scabies such as burrows, nodules on the genitalia, widespread crusted plaques, and complaints of pruritus can be absent. In this case of a patient with a generalised non-specific dermatitis, the predominance of scale in the webspaces was the key clinical clue to the diagnosis.

Fig 1

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