Probability of Developing Psoriasis

Psoriasis affects approximately 7.5 million American adults (about 3% of the adult population), making it one of the most common autoimmune diseases. It is a chronic condition characterized by patches of thick, red, scaly skin that can appear anywhere on the body but most commonly affects the scalp, elbows, knees, and lower back.

Psoriasis typically first appears between ages 15-25, though it can develop at any age. It has a strong genetic component (about 40% heritability), and triggers include stress, infections (particularly streptococcal throat infections), certain medications (lithium, beta-blockers, antimalarials), cold weather, and skin injury (the Koebner phenomenon). Psoriasis affects men and women equally and all racial/ethnic groups, though prevalence varies.

Beyond skin symptoms, psoriasis is associated with significantly increased risk of psoriatic arthritis (affecting about 30% of psoriasis patients), cardiovascular disease, metabolic syndrome, depression, and inflammatory bowel disease. Treatment has been revolutionized by biologic medications (TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors), which can achieve clear or almost clear skin in 60-90% of patients. Other treatments include topical corticosteroids, phototherapy, and oral systemic medications. Psoriasis costs the US healthcare system approximately $35 billion per year.