Psoriasis

Question 1

What is psoriasis?

Answer 1

A chronic, immune-mediated inflammatory skin disorder characterized by hyperproliferation of keratinocytes and systemic inflammation.

Question 2

What are the most common clinical subtypes of psoriasis?

Answer 2

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.

Question 3

What is the prevalence of psoriasis?

Answer 3

Approximately 2–3% of the global population.

Question 4

What drives the pathogenesis of psoriasis?

Answer 4

Dysregulated immune response involving T-cells (Th1, Th17) and cytokines (e.g., IL-17, IL-23, TNF-α) leads to keratinocyte hyperproliferation and inflammation.

Question 5

What genetic factors are associated with psoriasis?

Answer 5

Strong familial predisposition.

Associated with HLA-Cw6 (particularly in early-onset psoriasis).

Question 6

What are the hallmark features of plaque psoriasis?

Answer 6

Well-demarcated, erythematous plaques with silvery-white scales.

Commonly affects the scalp, elbows, knees, and lower back.

Question 7

What is the Auspitz sign?

Answer 7

Pinpoint bleeding when psoriatic scales are removed, due to capillary involvement.

Question 8

What is Koebner phenomenon?

Answer 8

Development of psoriatic lesions at sites of trauma or injury.

Question 9

What are nail changes associated with psoriasis?

Answer 9

Pitting.

Onycholysis (separation of nail from bed).

Oil-drop sign (yellow-brown discoloration).

Subungual hyperkeratosis.

Question 10

What is guttate psoriasis commonly associated with?

Answer 10

Streptococcal throat infections.

Question 11

How does inverse psoriasis present?

Answer 11

Erythematous plaques without scales in intertriginous areas (e.g., groin, axilla, under breasts).

Question 12

What are the features of pustular psoriasis?

Answer 12

Sterile pustules on an erythematous base.

Can be localized (e.g., palms and soles) or generalized (life-threatening).

Question 13

What characterizes erythrodermic psoriasis?

Answer 13

Diffuse erythema and scaling involving most of the body surface.

Associated with systemic symptoms (e.g., fever, malaise).

Question 14

What are common triggers for psoriasis flares?

Answer 14

Trauma (Koebner phenomenon).

Infections (e.g., streptococcal pharyngitis).

Stress.

Medications (e.g., β-blockers, lithium, antimalarials, NSAIDs).

Alcohol and smoking.

Question 15

What systemic conditions are associated with psoriasis?

Answer 15

Psoriatic arthritis.

Metabolic syndrome.

Cardiovascular disease.

Depression and anxiety.

Question 16

How is psoriasis diagnosed?

Answer 16

Clinically, based on characteristic skin lesions and history. Skin biopsy may be used for atypical cases.

Question 17

What are key histological findings in psoriasis?

Answer 17

Hyperkeratosis and parakeratosis.

Epidermal acanthosis (thickened epidermis).

Elongation of dermal papillae.

Munro microabscesses (collections of neutrophils in the stratum corneum).

Question 18

What are the first-line treatments for mild to moderate psoriasis?

Answer 18

Topical corticosteroids.

Vitamin D analogs (e.g., calcipotriol).

Coal tar.

Topical retinoids (e.g., tazarotene).

Question 19

What systemic treatments are used for moderate to severe psoriasis?

Answer 19

Methotrexate: Reduces inflammation and keratinocyte proliferation.

Cyclosporine: Rapid onset, used for severe cases.

Acitretin: A systemic retinoid for pustular or erythrodermic psoriasis.

Question 20

What are biologic therapies for psoriasis?

Answer 20

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).

Question 21

How is phototherapy used in psoriasis?

Answer 21

Narrowband UVB or PUVA (psoralen + UVA) is effective for widespread lesions.

Question 22

What is psoriatic arthritis, and how does it present?

Answer 22

An inflammatory arthritis associated with psoriasis, presenting with joint pain, stiffness, and swelling, often affecting the distal interphalangeal joints.

Question 23

What factors indicate a worse prognosis in psoriasis?

Answer 23

Early onset, severe disease, and associated comorbidities like arthritis or metabolic syndrome.