Psoriasis

Psoriasis is a chronic condition where skin cells grow much too quickly. Normally, a skin cell takes about a month to form and shed. In psoriasis, that happens in just a few days. The extra cells pile up on the surface, forming thick, raised patches with silvery scales.

The cause is an overactive immune system. Your immune system mistakenly treats healthy skin as a threat and creates inflammation. That inflammation is what speeds up the skin cells.

This is the key thing to understand: psoriasis is not just a skin problem. The same inflammation runs through the whole body. That is why psoriasis is linked to joint disease, heart disease, and other conditions. Treating it is about more than clearing the skin.

Psoriasis can start at any age, but usually appears between 15 and 25. It affects all genders and skin tones. There is no cure, but today's treatments control it very well for most people.

This page covers plaque psoriasis, which is about 90% of all cases.

Red or discolored raised patches. These are covered with thick, silvery-white scales. On darker skin tones, patches may look purple, gray, or dark brown rather than red.

Itching and burning. The patches can itch, sting, or feel sore.

Dry, cracked skin. Skin may split and bleed.

Nail changes. Fingernails and toenails can become thickened, ridged, or pitted (small dents).

Stiff, swollen joints. Some people develop psoriatic arthritis. This causes joint pain, swelling, and stiffness.

Scalp flaking. About half of people with psoriasis have it on the scalp.

Where it shows up. Most often the elbows, knees, scalp, and lower back. Less commonly the armpits, under the breasts, groin, genitals, hands, and feet.

The exact cause is not fully known, but two things drive it:

An overactive immune system. Your immune system sends faulty signals that create inflammation and speed up skin cell growth.

Genetics. Psoriasis runs in families. Certain genes make you more likely to develop it, though you usually need a trigger to set it off.

Psoriasis is not contagious. You cannot catch it from someone else, and you cannot give it to anyone.

Smoking. Increases both your risk of getting psoriasis and how severe it gets.

Heavy alcohol use. Can set off flares.

Stress. A very common trigger.

Infections. Strep throat in particular can trigger psoriasis, especially in young people.

Skin injury. Cuts, scrapes, tattoos, and sunburns can cause new patches to form right at the injured spot. This is called the Koebner phenomenon.

Cold, dry weather. Winter usually makes psoriasis worse.

Certain medications. Beta-blockers, lithium, and antimalarial drugs can trigger or worsen it.

Stopping prednisone suddenly. This can cause a severe rebound flare. Never stop an oral steroid without your doctor's guidance.

Excess weight. Linked to higher risk and more severe disease.

A dermatologist can usually diagnose psoriasis just by looking at your skin, nails, and scalp. No special test is needed in most cases.

Expect questions like:

• When did you first notice it?
• Does anyone in your family have psoriasis?
• Is this your first flare?
• Do you have any joint pain or stiffness?
• What products or shampoos do you use?

Sometimes a small skin sample (a biopsy) is taken to look at under a microscope. This confirms the diagnosis and rules out look-alike conditions.

Your doctor should also ask about your joints. Psoriatic arthritis can be missed in its milder forms, and catching it early prevents permanent joint damage.

Good daily habits make a real difference, and they support whatever treatment you are on.

Moisturize, generously. Use a thick, fragrance-free moisturizer. Look for urea or lactic acid, which help soften scale.

Remove scale gently. Salicylic acid products and coal tar help lift flakes. Oils can soften them before you wash.

Take lukewarm oatmeal baths. Colloidal oatmeal soothes itch. Skip hot water, which dries skin out.

Try OTC hydrocortisone on small areas to calm redness and itch. Do not overuse it.

Wear soft, loose cotton clothing. Rough fabric irritates patches.

Protect your skin from injury and sunburn. Both can trigger new patches.

Lifestyle changes that help: don't smoke, limit alcohol, stay active, keep a healthy weight, sleep well, and manage stress. These are not side notes — psoriasis is an inflammatory disease, and these habits lower inflammation.

Over-the-counter products work best for mild psoriasis, and they support prescription treatment in more severe cases. Look for these ingredients:

To soften and remove scale: salicylic acid, coal tar, and oils.

To moisturize: thick, fragrance-free creams with urea or lactic acid.

To calm inflammation: OTC hydrocortisone (1%).

Coal tar is worth knowing about. It slows skin cell growth and reduces itching and scaling. It smells strong and can stain, but it works.

Regular, consistent use matters more than any single product.

When OTC products aren't enough, prescription treatment is the next step. What you get depends on where the psoriasis is and how much skin it covers.

Topical steroids. Reduce inflammation and itch. They come in many strengths. Long-term use can thin the skin, so doctors limit how long you use them. Examples: hydrocortisone, triamcinolone, betamethasone, clobetasol.

Vitamin D creams. Slow skin cell growth. Few side effects, and often paired with a steroid. Examples: calcipotriene, Dovonex.

Elidel and Protopic. Non-steroid creams that calm inflammation. Safe for delicate areas like the face, armpits, and groin, where steroids are risky.

Vitamin A creams (Tazorac). Slow skin cell growth. Can cause irritation and dryness.

Otezla. A twice-daily pill. Reduces inflammation. Common side effect is diarrhea. Not as strong as biologics, but fewer side effects.

Sotyktu. A once-daily pill. Few side effects, but needs monitoring.

Biologics. Injections you give yourself at home. These target the immune signals driving psoriasis and are very effective for moderate to severe disease. They need regular monitoring. Examples: Humira, Stelara, Cosentyx, Skyrizi.

Prednisone. An oral steroid. Used rarely and only short-term. Stopping it suddenly can cause a severe rebound flare, so it is not a preferred option.

A note on cost: biologics and newer pills are expensive, and insurers often deny them at first. Ask your dermatologist's office about prior authorization and manufacturer copay programs before you give up.

When creams and pills aren't enough, phototherapy is the next option. It uses controlled ultraviolet (UV) light to calm inflammation and slow skin cell growth.

Office phototherapy. UVB light delivered in a clinic, usually 2–3 times a week. Effective for moderate to severe psoriasis.

Home phototherapy. A prescription device you use at home. Similar to the office unit. Check whether your insurance covers it under "Durable Medical Equipment (DME)."

OTC phototherapy devices. Small handheld units you can buy online. Reasonable for mild to moderate psoriasis on limited areas.

Phototherapy is safe and well-studied. It is a good middle step between topicals and systemic drugs.

See a dermatologist if:

• Over-the-counter treatment isn't controlling it
• Psoriasis covers more than a few small patches
• It's on your face, scalp, hands, feet, or genitals
• Your joints ache, swell, or feel stiff — especially in the morning
• The itch is affecting your sleep or daily life
• It's affecting your mood or how you feel about yourself

That joint symptom is the important one. Psoriatic arthritis can cause permanent damage if it's not caught early, and it's easy to dismiss as ordinary aches.

Eczema. The most common mix-up. Eczema is usually more intensely itchy, less thick, and shows up in skin folds (inner elbows, behind knees). Psoriasis is thicker, more sharply outlined, has silvery scale, and favors the outside of elbows and knees.

Seborrheic dermatitis / dandruff. On the scalp, dandruff makes loose white-yellow flakes with mild itch. Scalp psoriasis makes thick silvery scale on red, raised skin, and often crosses the hairline onto the forehead or behind the ears.

Fungal infection (ringworm). Usually a ring shape with a clearer center. Psoriasis patches are filled in, not ring-shaped.

Lichen planus. Purple, flat-topped bumps, often on wrists and ankles.

If you're unsure, a dermatologist can tell the difference by looking, and a biopsy settles it.