Psoriasis

Background

• Often begins in the 2nd or 3rd decade of life
  • Chronic and relapsing

Triggers

• Stress
• Trauma
• Drugs

Clinical Presentation

Psoriatic plaque, showing a silvery center surrounded by a reddened border.

Psoriasis before and after treatment.

• Well-demarcated erythematous plaques and papules with silvery white scales
  • Epidermal hyperproliferation
• Commonly found on the trunk, scalp, nail pitting, and extensor surfaces
• Auspitz sign: plaque removal reveals pinpoint-bleeding areas
• Associated with psoriatic arthritis, especially in nail involvement

Differential Diagnosis

Other Rash

• Acute generalized exanthematous pustulosis
• Allergic reaction
• Aphthous stomatitis
• Atopic dermatitis
• Coxsackie
• Dermatitis herpetiformis
• Exfoliative erythroderma
• Impetigo
• Pellagra
• Pityriasis rosea
• Serum Sickness
• Tinea capitus
• Tinea corporis
• Vitiligo

Management

• Ketoconazole 2% shampoo
• Hydrocortisone cream 1%
• Systemic steroids should be avoided due to the risk of developing rebound or induction of pustular psoriasis

See Also

• Generalized rashes

References

• Uptodate
• Hess MR, Hess SP: Skin Disorders Common on the Trunck, in Tintinalli JE, Kelen GD, Stapczynski JS (eds): Emergency Medicine, A Comprehensive Study Guide, ed 7. New York, McGraw-Hill, 2011, (Ch) 249:p 1653-1654