Psoriasis

Etiology

  • Idiopathic inflammatory skin condition.

Risk Factors

  • Plaque psoriasis: affects 2-4% population (80% of psoriasis cases); m=w; age onset15-25, 50-60; etoh, hiv, stress, meds can precipitate
  • Guttate psoriasis: < 2% of cases of psoriasis; age < 30; often upper resp infxn w/grp A strep preceding skin eruption by few weeks.
  • Erythrodermic Psoriasis: 1-3% of psoriasis cases
  • Pustular psoriasis: < 1% of psoriasis; can be precipitated by administration of steroids, illness, severe stress
  • Psoriatic arthritis: affects 6-10% of patients w/psoriasis

Symptoms

  • Plaque psoriasis: chronic, often assoc w/itching; increased risk c/v dz; increased risk shame, embarrassment, depression, body image issues, neg impact on quality of life
  • Guttate psoriasis: abrupt presentation
  • Erythrodermic Psoriasis: large surface area develops generalized erythema, often w/f, chills, malaise
  • Psoriatic arthritis: psoriasis pre-dates arthritis by about 10y in most cases; sometimes arthritis and psoriasis occur simultaneously or w/arthritis first

Physical Exam Findings

  • Plaque psoriasis: well demarcated, scaly, pink to red, w/silver-white scale; symmetric distribution; extensor surface predominance; elbows, knees, scalp, trunk, inter-gluteal cleft, umbilicus; nail involvement w/pitting or other abnl in up to 50%
  • Inverse (flexural) psoriasis: axillary, genital/inguinal crease, infra-mammary, neck, perineum; well demarcated erythematous areas w/minimal scale
  • Guttate psoriasis: 1-10mm papules, fine scale, trunk and extremities
  • Erythrodermic Psoriasis: can affect >75% of body surface, superficial desquamation, hair loss, nail dystrophy
  • Pustular psoriasis: pustules that appear within or at edge of plaque psoriasis; can also be a generalized eruption; palms and plantar surfaces
  • Psoriatic arthritis: plaque psoriasis; multiple peripheral joints w/pain, warmth, redness.

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