Psoriasis affects more than 8 million people in the United States, according to the National Psoriasis Foundation. The disease occurs equally in men and women, and people typically have their first outbreak between the ages of 15 and 25. Psoriasis most often occurs on the elbows, knees, scalp, lower back, face, palms and soles of the feet.

Normally, skin cells mature and shed from the body after about a month. If you suffer from psoriasis, cell maturation increases, taking only three to four days. This causes dead skin cells to accumulate in thick patches resulting in lesions, which can itch, burn, crack or cause restricted movement.

Types of Psoriasis

Psoriasis is chronic and unpredictable. Symptoms can come on suddenly and disappear just as quickly. There are five common types of psoriasis, each with its own characteristic skin lesion:

  • Plaque psoriasis—Raised, inflamed, red lesions covered by a silvery, white buildup of dead skin cells primarily affecting the trunk, elbows, knees, scalp, fingernails and toenails. This is the most common form of psoriasis.
  • Erythrodermic psoriasis—Red, swollen lesions that appear on large areas of skin.
  • Guttate psoriasis—Small, drop-like lesions that appear on the trunk, limbs and scalp.
  • Inverse psoriasis—Large, dry, smooth, red lesions that appear in the folds of skin.
  • Pustular psoriasis—Small, blister-like lesions that contain white pus found either all over the body or confined to the palms and soles. This form of psoriasis occurs most often in children.

Causes

The exact cause of psoriasis is unknown, but it seems that the immune system somehow mistakenly triggers T cells in the skin. T cells trigger excessive skin cell reproduction, speeding up the growth cycle. Your genetic makeup may determine if you are likely to develop psoriasis, but not everyone with a genetic predisposition will develop the condition. Instead, certain triggers seem to awaken and activate the disease in those with a genetic predisposition, including:

  • Emotional stress
  • Injury to the skin
  • Immune system response to disease
  • Some types of infections
  • Reactions to certain drugs

People suffering from psoriasis may also notice that there are times when their skin worsens and then improves for no apparent reason. Some factors that may cause flare-ups include:

  • Changes in climate
  • Dry or sunburned skin
  • Alcohol
  • Medications
  • Infections

Treatment

There is no cure for psoriasis, but there are things you can do to help control your symptoms:

  • Keep the skin lubricated.
  • Use a humidifier in colder, dryer months.
  • Do not get too much sun.
  • Use mild soaps or soap-free cleansers.
  • Eat a nutritionally balanced diet and maintain a healthy weight.
  • Do not scratch, rub or pick the lesions.
  • Bathe daily to soak off the scales.
  • Use soaps, shampoos, cleansers or ointments containing coal tar or salicylic acid.