Psoriasis
Psoriasis is a chronic immune-mediated disease that speeds up skin cell growth, causing recurring patches that may itch, hurt, scale, crack, or bleed.
What psoriasis is
Psoriasis is a chronic disease in which the immune system becomes overactive and skin cells build up too quickly. The result can be patches of thickened, inflamed, scaly skin. Symptoms often come and go, with periods of improvement followed by flares.
How it differs from eczema
Psoriasis and eczema can both cause itchy, irritated skin, but they are different conditions. Psoriasis often creates thicker, more sharply defined plaques with silvery scale, while eczema is more strongly tied to skin-barrier dryness and atopic conditions. A clinician may be needed because rashes can overlap in appearance.
Symptoms and body areas
Psoriasis can affect the elbows, knees, scalp, lower back, palms, soles, nails, skin folds, and other areas. Patches may itch, sting, burn, crack, or bleed. Nails may pit, thicken, loosen, or change color. On darker skin, plaques may look purple, brown, gray, or darker rather than bright red.
Types of psoriasis
Plaque psoriasis is the most common type. Other forms include guttate psoriasis, inverse psoriasis, pustular psoriasis, and erythrodermic psoriasis. Each type has different patterns and severity. Some forms can be widespread or urgent, especially when large areas of skin become inflamed.
Flares and triggers
Psoriasis flares can be triggered by skin injury, infections, stress, cold or dry weather, smoking, heavy alcohol use, and some medicines. Not every flare has an obvious trigger. Genetics and immune pathways also play important roles, which is why psoriasis can run in families.
Psoriatic arthritis
Psoriatic arthritis is a joint condition that can occur with psoriasis. It may cause joint pain, stiffness, swelling, tendon pain, back pain, or sausage-like swelling of fingers or toes. Early recognition matters because untreated inflammatory arthritis can damage joints over time.
Diagnosis and treatment options
Clinicians usually diagnose psoriasis by examining the skin, scalp, nails, and symptoms. Sometimes a skin biopsy or other evaluation is used to rule out similar conditions. Treatment depends on type, severity, location, and overall health, and may include topical treatments, light therapy, oral medicines, injections, or biologic medicines.
Why it matters
Psoriasis matters because it is more than a cosmetic skin problem. It can affect sleep, comfort, clothing choices, work, mood, stigma, and joint health. Understanding psoriasis as an immune-mediated disease helps explain why care often combines skin treatment, trigger awareness, and attention to related health risks.