erythroderma

Eczema, psoriasis, drug eruptions and lichen planus
rarely progress to erythroderma, defined as erythema,
with or without scaling, affecting almost all the body
surface. In dark skin, the presence of pigmentation
may mask the erythema, giving a purplish hue. Other
causes include cutaneous T-cell lymphoma , the psoriasis-like condition pityriasis rubra pilaris, and rare types of ichthyosis.
Erythroderma may occur at any age and is associated with severe morbidity but rarely mortality. Older
people are at greatest risk. It may appear suddenly or
evolve slowly.
Erythrodermic patients, especially the elderly, may
be systemically unwell with shivering and hypothermia, secondary to excess and uncontrolled heat loss
caused by increased blood flow to their skin. However,
they may also be pyrexial, and unable to lose heat due to
damage to sweat gland function and sweat duct occlusion. Tachycardia and hypotension may be present, due
to volume depletion. Peripheral oedema is common in
erythroderma, due to low albumin and high-output
cardiac failure. Lymph nodes may be enlarged, either
reactive to skin inflammation, or rarely due to lymphomatous infiltration.