Psoriasis Flashcards
What is psoriasis?
A chronic, immune-mediated inflammatory skin disorder characterized by hyperproliferation of keratinocytes and systemic inflammation.
What are the most common clinical subtypes of psoriasis?
Plaque psoriasis (psoriasis vulgaris): Most common type, with well-demarcated, erythematous plaques and silvery scales.
Guttate psoriasis: Small, drop-shaped lesions often triggered by infections.
Inverse psoriasis: Erythematous plaques in skin folds (e.g., groin, axilla).
Pustular psoriasis: Sterile pustules on an erythematous base.
Erythrodermic psoriasis: Widespread erythema and scaling; a medical emergency.
What is the prevalence of psoriasis?
Approximately 2–3% of the global population.
What drives the pathogenesis of psoriasis?
Dysregulated immune response involving T-cells (Th1, Th17) and cytokines (e.g., IL-17, IL-23, TNF-α) leads to keratinocyte hyperproliferation and inflammation.
What genetic factors are associated with psoriasis?
Strong familial predisposition.
Associated with HLA-Cw6 (particularly in early-onset psoriasis).
What are the hallmark features of plaque psoriasis?
Well-demarcated, erythematous plaques with silvery-white scales.
Commonly affects the scalp, elbows, knees, and lower back.
What is the Auspitz sign?
Pinpoint bleeding when psoriatic scales are removed, due to capillary involvement.
What is Koebner phenomenon?
Development of psoriatic lesions at sites of trauma or injury.
What are nail changes associated with psoriasis?
Pitting.
Onycholysis (separation of nail from bed).
Oil-drop sign (yellow-brown discoloration).
Subungual hyperkeratosis.
What is guttate psoriasis commonly associated with?
Streptococcal throat infections.
How does inverse psoriasis present?
Erythematous plaques without scales in intertriginous areas (e.g., groin, axilla, under breasts).
What are the features of pustular psoriasis?
Sterile pustules on an erythematous base.
Can be localized (e.g., palms and soles) or generalized (life-threatening).
What characterizes erythrodermic psoriasis?
Diffuse erythema and scaling involving most of the body surface.
Associated with systemic symptoms (e.g., fever, malaise).
What are common triggers for psoriasis flares?
Trauma (Koebner phenomenon).
Infections (e.g., streptococcal pharyngitis).
Stress.
Medications (e.g., β-blockers, lithium, antimalarials, NSAIDs).
Alcohol and smoking.
What systemic conditions are associated with psoriasis?
Psoriatic arthritis.
Metabolic syndrome.
Cardiovascular disease.
Depression and anxiety.
How is psoriasis diagnosed?
Clinically, based on characteristic skin lesions and history. Skin biopsy may be used for atypical cases.
What are key histological findings in psoriasis?
Hyperkeratosis and parakeratosis.
Epidermal acanthosis (thickened epidermis).
Elongation of dermal papillae.
Munro microabscesses (collections of neutrophils in the stratum corneum).
What are the first-line treatments for mild to moderate psoriasis?
Topical corticosteroids.
Vitamin D analogs (e.g., calcipotriol).
Coal tar.
Topical retinoids (e.g., tazarotene).
What systemic treatments are used for moderate to severe psoriasis?
Methotrexate: Reduces inflammation and keratinocyte proliferation.
Cyclosporine: Rapid onset, used for severe cases.
Acitretin: A systemic retinoid for pustular or erythrodermic psoriasis.
What are biologic therapies for psoriasis?
TNF-α inhibitors (e.g., etanercept, adalimumab).
IL-17 inhibitors (e.g., secukinumab).
IL-23 inhibitors (e.g., guselkumab).
IL-12/23 inhibitors (e.g., ustekinumab).
How is phototherapy used in psoriasis?
Narrowband UVB or PUVA (psoralen + UVA) is effective for widespread lesions.
What is psoriatic arthritis, and how does it present?
An inflammatory arthritis associated with psoriasis, presenting with joint pain, stiffness, and swelling, often affecting the distal interphalangeal joints.
What factors indicate a worse prognosis in psoriasis?
Early onset, severe disease, and associated comorbidities like arthritis or metabolic syndrome.
