Erythrodermic Psoriasis

• Rare, severe, and potentially life-threatening form of psoriasis.
• Characterized by generalized inflammatory erythema classically involving ≥90% of the body surface area, although >80% is also used in descriptions specifically addressing erythrodermic psoriasis.
• Associated with extensive scaling and major impairment of the cutaneous barrier.
• Usually develops in patients with pre-existing psoriasis but may rarely be the initial presentation.
• A dermatologic emergency requiring urgent specialist assessment because of fluid, electrolyte, thermoregulatory, infectious, and cardiovascular complications.

TRIGGERS

• Abrupt withdrawal of systemic corticosteroids +++.
• Abrupt withdrawal or inappropriate modification of psoriasis therapy.
• Infection.
• Medications, including lithium and antimalarials.
• Hypocalcemia.
• Excessive alcohol consumption.
• Progression of unstable or poorly controlled psoriasis.

• Acute or progressive onset of generalized skin redness.
• Significant pruritus.
• Cutaneous warmth, burning, or pain may occur.
• Chills and systemic malaise.
• Fever or hypothermia may occur.
• Fatigue and weakness in patients with systemic involvement.

COMPLICATIONS

• Dehydration and substantial fluid loss.
• Electrolyte disturbances.
• Protein loss → hypoalbuminemia and edema.
• Hypothermia from impaired thermoregulation.
• High-output cardiac failure.
• Secondary bacterial infection ± sepsis.
• Malnutrition in prolonged disease.

• Intense, confluent generalized erythema.
• Diffuse scaling, ranging from fine scale to large sheets.
• Warm, thickened, sometimes edematous skin.
• Pruritus ± excoriations.
• Peripheral edema, especially of the lower extremities.
• Palmoplantar keratoderma may occur.
• Nail dystrophy, onycholysis, or nail shedding in prolonged disease.
• Possible alopecia and lymphadenopathy.

• Generalized +++, typically involving ≥90% of the body surface area.
• Extensive involvement of the trunk and extremities.
• Face and scalp are frequently involved.
• Palms and soles may be affected, with keratoderma.
• Some areas may be relatively spared, particularly the nasal/perinasal region (“nose sign”).

• Diffuse erythematous background.
• Regularly distributed dotted vessels, supporting a psoriatic origin.
• Diffuse white scaling.
• Findings may become less specific in extensive erythroderma.

• Primarily clinical, based on generalized erythroderma with features or history supporting psoriasis.
• Review medications, recent infections, and withdrawal/change of psoriasis therapy.
• CBC, electrolytes, renal/liver function, albumin ± inflammatory markers to assess systemic complications.
• Cultures when infection is suspected.
• Skin biopsy when the diagnosis or cause of erythroderma remains uncertain.

• Erythrodermic atopic dermatitis
• Drug eruption
• Pityriasis rubra pilaris
• Sézary syndrome / cutaneous T-cell lymphoma
• Generalized contact dermatitis
• Generalized immunobullous disease

• Urgent dermatology assessment; hospitalization is frequently required for acute or systemically unwell patients.
• Monitor temperature, hemodynamic status, fluid balance, and electrolytes.
• Fluid and electrolyte replacement.
• Liberal bland emollients and wet/cooling dressings.
• Nutritional support when significant protein loss occurs.
• Antibiotics only for suspected or confirmed bacterial infection.
• Cyclosporine is a traditional rapid-acting systemic option for acute disease; methotrexate and acitretin are alternatives depending on the clinical context.
• Biologics, particularly IL-17 and IL-23 inhibitors, are increasingly used; however, erythrodermic-specific evidence remains more limited than evidence for plaque psoriasis.
• Avoid systemic corticosteroids when possible, particularly because withdrawal may precipitate severe rebound psoriasis.
• Avoid phototherapy and topical tar during the acute phase, as they may worsen erythroderma.