Page 59 - LECTURE NOTES

skin thickens, and scaling continues and becomes lamellar. There is a loss of scalp

and body hair, the nails become thickened and separated from the nail bed
(onycholysis), and there may be hyperpigmentation or patchy loss of pigment in

patients whose normal skin color is brown or black.

About 50% of the patients with EES have a history of a preexisting dermatosis, which is
recognizable only in the acute or subacute stages. The most frequent preexisting skin

disorders are (in order of frequency) psoriasis, eczematous dermatitis (atopic, allergic

contact, seborrheic), adverse cutaneous drug reaction, lymphoma, and pityriasis rubra
pilaris. Drugs most commonly implicated in erythroderma are found In 10 to 20% of

patients it is not possible to identify the cause by history or histology.

Pathogenesis

The metabolic response to exfoliative dermatitis may be profound. Large amounts of
warm blood are present in the skin due to the dilatation of capillaries, and there is

considerable heat dissipation through insensible fluid loss and by convection. Also,

there may be high output cardiac failure; the loss of scales through exfoliation can be
considerable, up to 9 g/m2 of body surface per day, and this may contribute to the

reduction in serum albumin and the edema of the lower extremities so often noted in
these patients.

Systemic changes associated with exfoliative dermatitis and erythroderma
i. Hypothermia and hyperthermia

ii. Fluid and electrolyte disturbance
iii. Sepsis

iv. Pyrexia occurs due to pyrogens transcutaneously.
v. Hypoprotienemia from exfoliation

vi. Anemia

vii. Vitamin deficiency states
viii. By unknown mechanism they have they have GIT disorders such as mal

absorption.

53