Definition
- Erythema and scaling affecting ≥ 80 to 90% of the body surface area.
- Primary: starts on trunk and extends to whole body within days-weeks
- Secondary: generalization of pre-existing localized skin disease
Epidemiology
- M:F of 2-4:1 (higher for idiopathic)
- Average of onset 52 years of age
- In adults 20-30% relapse rates at one year
Pathogenesis:
- Poorly understood for the de novo genesis of erythroderma
- Possible role for age-related immune senescence in idiopathic type and immune disregulation in children with immunodeficiencies
- Increased number and mitotic rate of germinative keratinocytes + shortened transit time through epidermis
- Consequence: Increased daily scale loss (20-30g/day) leading to systemic manifestations secondary to fluid/protein loss
Cutaneous Manifestations:
- Pruritus (90% of patients)
- Lichenification
- Dyspigmentation (hypo>hyper)
- Palmoplantar keratoderma
- Alopecia
- Nail dystrophy (40%)
- Shiny (most common)
- Pits
- Horizontal ridging (atopic dermatitis)
- Brittleness
- Dullness
- Discoloration
- Subungual hyperkeratosis
- Beau’s lines
- Paronychia
- Splinter hemorrhages
- Total nail shedding
- Ectropion
- Purulent conjunctivitis
- Seborrheic keratosis
- S. Aureus colonization with secondary cutaneous infection
Systemic Manifestations:
- Peripheral edema
- Facial edema
- Hypoalbuminemia
- Loss of fluid
- Tachycardia
- High output cardiac failure
- Electrolytes imbalance
- Thermoregulatory disturbances (hyper> hypothermia)
- Cachexia
- Anemia (iron deficiency and of chronic disease)
- Bacteremia
- Hepatomegaly (> with drug induced hypersensitivity)
- Splenomegaly
- Lymphadenopathy (most common extracutaneous manifestation)
- Acute respiratory distress syndrome
Approach:
- Complete history and physical examination
- Skin biopsy +/- direct immunofluorescence
- If lymphadenopathy: lymph node biopsy (core or excisional), immunohistochemistry, T-cell receptor analysis ± CT or PET-CT
- Investigations based on clinical suspicion of underlying disorder
