Psoriasis – Symptoms and causes – Mayo Clinic

Symptoms

Psoriasis signs and symptoms are different for everyone. Common signs and symptoms include:

Psoriasis patches can range from a few spots of dandruff-like scaling to major eruptions that cover large areas.

Most types of psoriasis go through cycles, flaring for a few weeks or months, then subsiding for a time or even going into complete remission.

There are several types of psoriasis. These include:

Guttate psoriasis. This type primarily affects young adults and children. It's usually triggered by a bacterial infection such as strep throat. It's marked by small, water-drop-shaped, scaling lesions on your trunk, arms, legs and scalp.

The lesions are covered by a fine scale and aren't as thick as typical plaques are. You may have a single outbreak that goes away on its own, or you may have repeated episodes.

Pustular psoriasis. This uncommon form of psoriasis can occur in widespread patches (generalized pustular psoriasis) or in smaller areas on your hands, feet or fingertips.

It generally develops quickly, with pus-filled blisters appearing just hours after your skin becomes red and tender. The blisters may come and go frequently. Generalized pustular psoriasis can also cause fever, chills, severe itching and diarrhea.

If you suspect that you may have psoriasis, see your doctor for an examination. Also, talk to your doctor if your psoriasis:

Seek medical advice if your signs and symptoms worsen or don't improve with treatment. You may need a different medication or a combination of treatments to manage the psoriasis.

The cause of psoriasis isn't fully understood, but it's thought to be related to an immune system problem with T cells and other white blood cells, called neutrophils, in your body.

T cells normally travel through the body to defend against foreign substances, such as viruses or bacteria.

But if you have psoriasis, the T cells attack healthy skin cells by mistake, as if to heal a wound or to fight an infection.

Overactive T cells also trigger increased production of healthy skin cells, more T cells and other white blood cells, especially neutrophils. These travel into the skin causing redness and sometimes pus in pustular lesions. Dilated blood vessels in psoriasis-affected areas create warmth and redness in the skin lesions.

The process becomes an ongoing cycle in which new skin cells move to the outermost layer of skin too quickly in days rather than weeks. Skin cells build up in thick, scaly patches on the skin's surface, continuing until treatment stops the cycle.

Just what causes T cells to malfunction in people with psoriasis isn't entirely clear. Researchers believe both genetics and environmental factors play a role.

Psoriasis typically starts or worsens because of a trigger that you may be able to identify and avoid. Factors that may trigger psoriasis include:

Anyone can develop psoriasis, but these factors can increase your risk of developing the disease:

If you have psoriasis, you're at greater risk of developing certain diseases. These include:

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Psoriasis - Symptoms and causes - Mayo Clinic