- Erythrodermic psoriasis: generalized erythema covering >90% BSA – can cause hemodynamic instability
- Generalized pustular psoriasis: fever, sterile pustules – dermatologic emergency
- Psoriatic arthritis: joint pain, dactylitis, enthesitis – can cause permanent joint damage if untreated
Moderate‑to‑Severe Plaque Psoriasis
Must-Not-Miss / Red Flags
Patient Explanation
“You have a skin condition called psoriasis, where your skin cells grow too quickly, causing red, scaly patches. It’s not contagious, and we have many treatments to help clear your skin.”
Board Fact
“The most common type is chronic plaque psoriasis (psoriasis vulgaris), affecting 90% of patients; nail changes and psoriatic arthritis occur in 30%.”
ICD-10
L40.0
Definition & Core Concept
Psoriasis is a chronic, immune‑mediated inflammatory skin disease characterized by well‑demarcated, erythematous plaques with silvery scales, resulting from accelerated epidermal proliferation and T‑cell driven inflammation.
Epidemiology & Risk Factors
- Prevalence: 2‑3% worldwide
- Bimodal onset: 20‑30 years and 50‑60 years
- Genetic component; HLA‑Cw6 is the strongest association
Clinical Vignette
A 35‑year‑old man has a 10‑year history of thick, scaly plaques on both elbows and knees, with new patches on his lower back. BSA involvement is 12%. He reports morning stiffness in his fingers. Dermatology Life Quality Index (DLQI) score is 18, indicating severe impact on quality of life.
Pearls & Pitfalls
- Psoriasis is not just a skin disease – actively screen for psoriatic arthritis and cardiovascular risk factors.
- Topical steroids should be used intermittently to avoid tachyphylaxis and skin atrophy.
Discharge & Follow-Up
Dermatology follow‑up every 3‑6 months to assess treatment response. PASI or BSA documentation for objective tracking. Annual screening for cardiovascular risk factors.
Literature & Guidelines
AAD‑NPF 2024 Guidelines for Psoriasis. PMID: 38629901.