Rarely, a psoriatic patient may develop a sudden or subacute appearance of generalized scaling and/or erythema (Fig. 14.30) which is referred to as exfoliative dermatitis (ED) or erythroderma (in the United Kingdom) and l'homme rouge (in France).

In adults, psoriasis is the most frequently associated underlying cause of ED.

ED can be the presenting symptom of psoriasis or a subsequent complication of psoriatic disease (for a more comprehensive discussion of ED, see Chapter 34: Cutaneous Manifestations of Systemic Disease).

Other triggers that have been reported to result in ED include the administration of systemic corticosteroids in patients with pre-existing psoriasis, a severe contact dermatitis, high levels of emotional stress, a medical procedure (e.g., surgery), or severe infections.

Appears suddenly or gradually, may become generalized, occasionally accompanied by fever, chills, and lymphadenopathy.

ED may be a stage in the natural history of severe psoriasis.

Marked generalized erythema is followed by scaling (see Figs. 14.30 and 14.31).

There is edema and increased warmth of the skin.

Lymphadenopathy, usually a reactive type (dermatopathic lymphadenopathy), is often present.

Thermoregulatory disturbances are manifested by fever or, more frequently, hypothermia.

Protein loss secondary to a massive shedding of scale may occur, with resultant hypoalbuminemia.

Rarely, high-output cardiac failure may develop, particularly in patients with a history of cardiac disease.

The diagnosis of ED due to psoriasis is made on a clinical basis.

Clinical findings, such as the characteristic nail pitting, or a history that suggests psoriasis, may be found.