According to the National Institutes of Health, psoriasis occurs when dead skin cells rise to quickly from beneath the layers of skin and pile up on the surface before the cells have matured. This process, known as cell turnover, usually takes about a month, but in psoriasis it may occur in only a few days.

The 30-year-old reality TV star Kim Kardashian was diagnosed Sunday with psoriasis, an autoimmune skin disease that affects about 7.5 million Americans. Symptoms can range from a mild skin rash to psoriatic arthritis, a potentially debilitating joint condition. The thick patches of red skin commonly occur on the scalp, knees, elbows and torso, but can appear on other parts of the body, according to the National Psoriasis Foundation.

Other symptoms for Psoriasis may include:

  • Genital lesions in males
  • Joint pain or aching (psoriatic arthritis)
  • Nail changes, including nail thickening, yellow-brown spots, dents (pits) on the nail surface, and separation of the nail from the base
  • Severe dandruff on the scalp

Health officials say bacteria or viral infections, including strep throat and upper respiratory infections, dry air or dry skin, injury to the skin, including cuts, burns, and insect bites, too little sunlight and alcohol, and stress can trigger the skin disease and make it more difficult to treat.

"Psoriasis comes in three different levels of severity, and it depends on the level of severity that dictates treatment," Catie Coman, director of communications for the National Psoriasis Foundation, told ABC News. "The population can often be very cruel because they think the disease is contagious or has to do with being dirty," she added. "Celebrities with psoriasis are under intense pressure, and stress is a trigger for psoriasis."

Health officials from the National Institutes of Health add that psoriasis occurs when the immune system sends out faulty signals that speed up the growth cycle of skin cells, and is not contagious. Sometimes, a skin biopsy is necessary to rule out other possible conditions, and should you have joint pain, your doctor may order x-rays.

Psoriasis is not curable, but it is treatable in many forms.

Traditional treatments prescribed by doctors for patients with psoriasis are medicines with vitamin A or D, cortisone creams, ointments and moisturizers. Although, the more common method is a three treatment option:

  • Topical medications: such as lotions, ointments, creams, and shampoos
  • Body-wide medications: pills or injections that affect the whole body, not just the skin
  • Phototherapy: therapy that uses light to treat psoriasis

Psoriasis is often misdiagnosed as a rash, ringworm or other skin irritation, such as eczema, according to the foundation. The group adds that although the disease cannot be cured, there are a variety of effective treatments available, including topical therapy.