Author: Vanessa Ngan, Staff Writer, 2003. Updated by A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, July 2014.
Disseminated secondary eczema is an acute, generalised eczema/dermatitis that arises in response to a prior localised inflammatory skin disease.
It is also called an id reaction, autosensitisation dermatitis and autoeczematisation.
The cause of disseminated secondary eczema is unknown. Theories have suggested it is an immune response to some component of the skin and/or to circulating infectious agents or cytokines (messenger proteins).
Disseminated secondary eczema can occur in children and adults, but is more often diagnosed in the elderly with a neglected primary rash on the lower leg.
The most common types of eczema / dermatitis that precede disseminated secondary eczema—an eczematid—are:
Infections preceding disseminated secondary eczema include:
Disseminated secondary eczema presents as an acute, symmetrical, generalised acute eczema. It tends to be extremely itchy, disturbing sleep.
The clinical features of disseminated secondary eczema are characteristic. Finding the cause depends on taking a careful history of the initial site of a skin problem. Sometimes the patient does not associate a chronic minor rash with their current widespread and symptomatic eruption.
Additional investigations that may be considered include:
Patch testing should not be undertaken during the acute phase of disseminated secondary eczema, but may be planned in several months when it has settled.
The secondary eczema is often extensive and highly symptomatic. Treatment may entail:
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