Psoriasis

Psoriasis is a chronic immune-mediated disease that causes rapid buildup of skin cells, resulting in scaling, inflammation, and redness. The most common form, plaque psoriasis, produces thick, red patches with silvery scales, often on the elbows, knees, scalp, and lower back.

Psoriasis is not contagious. It is associated with systemic inflammation and an increased risk of psoriatic arthritis, cardiovascular disease, metabolic syndrome, and depression. Severity ranges from a few mild plaques to nearly total body involvement. Modern treatments — including targeted biologics — can achieve clear or almost clear skin for many people.

Symptoms vary by type of psoriasis:

• Plaque psoriasis — raised, red patches covered with silvery scales; may be itchy or painful
• Nail psoriasis — pitting, abnormal nail growth, discoloration, or separation from the nail bed
• Guttate psoriasis — small, drop-shaped lesions often triggered by strep infection, especially in children and young adults
• Inverse psoriasis — smooth red patches in skin folds
• Pustular psoriasis — white pustules surrounded by red skin (can be localized or generalized and severe)
• Erythrodermic psoriasis — widespread redness and scaling that can be life-threatening

Psoriatic arthritis causes joint pain, stiffness, and swelling and can occur with or without significant skin disease.

Psoriasis is driven by an overactive immune response, particularly involving T cells and cytokines such as TNF-alpha, IL-17, and IL-23. This leads to accelerated growth of skin cells (days instead of weeks). Genetics play a major role; environmental triggers that can provoke onset or flares include:

• Infections (especially streptococcal)
• Skin injury (Koebner phenomenon)
• Stress
• Smoking and heavy alcohol use
• Certain medicines (lithium, some beta-blockers, antimalarials, rapid steroid taper)
• Cold, dry weather

Risk factors include:

• Family history of psoriasis
• Viral and bacterial infections
• Stress
• Obesity
• Smoking
• Heavy alcohol consumption
• Young adulthood is a common time of onset, with a second peak later in life

People with psoriasis have higher rates of:

• Psoriatic arthritis
• Eye conditions (conjunctivitis, uveitis)
• Obesity, type 2 diabetes, and metabolic syndrome
• High blood pressure and cardiovascular disease
• Other autoimmune diseases (e.g., inflammatory bowel disease, celiac disease)
• Parkinson’s disease (small increased risk in some studies)
• Kidney disease
• Emotional problems such as low self-esteem, depression, and social isolation

Psoriasis itself cannot be prevented, but flares can often be reduced by:

• Keeping skin moisturized
• Avoiding known personal triggers
• Not smoking and limiting alcohol
• Managing stress
• Maintaining a healthy weight
• Using prescribed treatments consistently

Diagnosis is usually clinical. A dermatologist can often recognize psoriasis by appearance and distribution. A skin biopsy is sometimes performed to confirm the diagnosis or rule out other conditions. Evaluation for psoriatic arthritis (history, joint exam, imaging when needed) is important because early treatment protects joints.

See a dermatologist or primary-care clinician if you have persistent red, scaly patches that do not improve with over-the-counter care, or if psoriasis is affecting your quality of life, sleep, or joints. Seek urgent care for widespread redness, pustules with fever, or severe joint symptoms.

Treatment is stepped according to severity and impact:

Topical therapies — corticosteroids, vitamin D analogues, calcineurin inhibitors, retinoids, coal tar, salicylic acid, and fixed-combination products.

Phototherapy — narrowband UVB, PUVA, or excimer laser under medical supervision.

Systemic traditional agents — methotrexate, cyclosporine, acitretin.

Biologics and targeted oral agents — TNF inhibitors, IL-17 inhibitors, IL-23 inhibitors, IL-12/23 inhibitors, PDE4 inhibitors (apremilast), and TYK2 inhibitors. These have transformed outcomes for moderate to severe psoriasis and psoriatic arthritis.

Treatment choice considers extent of disease, joint involvement, comorbidities, safety, cost, and patient preference. Many patients need combination or sequential therapy.

Helpful daily measures:

• Moisturize regularly with fragrance-free creams or ointments
• Take short, lukewarm baths with colloidal oatmeal or Epsom salts; pat dry and moisturize immediately
• Use medicated shampoos for scalp involvement
• Avoid picking or scratching plaques
• Protect skin from injury and sunburn (moderate sun exposure may help some people but increases skin-cancer risk)
• Maintain a healthy weight and stay active
• Seek support for the emotional impact of visible skin disease

Bring:

• Description of when lesions started, distribution, and prior treatments
• Joint symptoms if any
• List of medicines and family history of psoriasis or autoimmune disease
• Photos of lesions at their worst if they fluctuate
• Questions about topical vs systemic options, biologics, pregnancy, and monitoring