AAD Psoriasis Guidelines: Biologics and Systemic Therapy

Overview / Definition Psoriasis is a chronic, immune-mediated inflammatory skin condition characterized by the rapid proliferation of keratinocytes leading to scaling and plaques. It can affect various body regions, including the scalp, elbows, knees, and nails, and can significantly impact patients' quality of life. Epidemiology Psoriasis affects approximately 2-3% of the population in the United States, with a higher prevalence in Caucasian populations. The onset can occur at any age, but it commonly presents in two peaks: early adulthood (ages 15-30) and later adulthood (ages 50-60). Genetic predisposition: Family history is common in many patients. Environmental triggers: Infections, stress, and skin injuries can precipitate flares. Comorbidities: Associated with obesity, diabetes, and cardiovascular diseases. Pathophysiology / Mechanism The underlying pathophysiology of psoriasis involves an interplay of genetic, immune, and environmental factors. Activation of the immune system leads to a cascade of inflammatory cytokines, particularly TNF-alpha, IL-17, and IL-23, which play crucial roles in keratinocyte proliferation and inflammation. Keratinocyte hyperproliferation: Results in the characteristic thick, scaly plaques. Immune dysregulation: T cells and dendritic cells contribute to the inflammatory process. Angiogenesis: Increased blood vessel formation contributes to erythema. Clinical Presentation Psoriasis typically presents with well-demarcated, erythematous plaques covered with silvery-white scales. Common sites include: Scalp Elbows Knees Lower back Nails: Can show pitting and onycholysis. Other variants include: Guttate psoriasis: Often triggered by streptococcal infections, presenting with small, drop-like lesions. Inverse psoriasis: Occurs in skin folds, presenting as smooth, red plaques. Pustular psoriasis: Characterized by pustules, can be localized or generalized. Diagnosis / Workup Diagnosis is primarily clinical, based on the appearance of lesion