Psoriasis

Symptoms

People with psoriasis typically have pain and itching as a result of skin plaque and inflammation [Figure 1]. Psoriasis appears as raised red or purple skin that is dry and covered by flaky, white scales. It usually itches and burns, and in some cases the skin may crack. Psoriasis is especially common on elbows, knees, and the scalp. It may occur in small patches, or in larger swaths. Flaking from psoriasis of the scalp may look like dandruff.

Risk Factors

You may be predisposed to the disorder if your family has a history of psoriasis, Psoriasis tends to run in families, which indicates that it may be a genetic disorder. Although no one really knows what causes psoriasis, scientists think that a defect in the immune system causes white blood cells (lymphocytes) to trigger skin cells to form rapidly and build up.

Certain medications like beta blockers, lithium, and interferon can cause or aggravate psoriasis.

New psoriasis plaques often occur after the skin is damaged (e.g., cut, scratched, rubbed, or severely sunburned).