Psoriasis is a common skin inflammation (irritation and swelling) characterized by frequent episodes of redness, itching, and thick, dry, silvery scales on the skin.

Causes

• Inherited or genetic factors (passed down from parents) may play a role.

1. In a normal person, the new skin cells gradually move from lower layers to the surface (takes about a month), but in Psoriasis the process speeds up to a few days -- which results in piling up of dead skin cells (scales) in patches.

2. Evidence of genetic factors -- increased HLA antigen (white blood cell or leukocyte surface protein) and a strong family history in Psoriasis sufferers.

• The immune system (body's defenses) of disease-fighting cells (i.e., white blood cells and protein antibodies) may also play a role by misunderstanding internal communications and attacking skin and joints -- causing inflammation (irritation, swelling, pain) and damage.

Risk Factors

• Can occur at any age (even infants) but more common between 15-60.

• Male = female

• Family history -- especially in the younger patient

• Caucasians

• Factors that can initiate a flare up of Psoriasis include:
   

1. Local injury to the skin (sunburn, insect bites, Burns, and rashes)

2. Hormonal changes

3. Medications -- e.g., sudden discontinuation of steroids

4. Stress -- emotional or physical

5. Alcohol abuse

6. Obesity

7. Infections -- e.g., streptococcal throat infections (guttate Psoriasis)

8. Viral infections such as HIV

9. Weakened (e.g., in AIDS, cancer) or overactive immune system (as in autoimmune diseases like Rheumatoid Arthritis)

10. Cold climates

11. Lack of sunlight

12. Drugs such as anti-malarial medications

13. Increased blood Uric acid levels in some patients

Symptoms

• Skin patches -- red, dry, and covered with silvery scales

• Pustules

• Blisters

• Nail changes

• Itching

• Patches and itching may involve the scalp

• Joint pain (arthritis)

Screening and Diagnostics

• Your doctor may consult with a dermatologist (skin doctor).

• History

• Medical exam will reveal the patches and the other signs.

1. Koebner's phenomenon describes a psoriatic response (patches, scales, etc.) that occurs in an area where an injury to the skin took place 1-2 weeks earlier.

2. Blood tests may be done for ESR (if elevated, it indicates inflammation), complete blood cell count (often shows increase in white blood cells), Uric acid levels, Rheumatoid factor (to rule out Rheumatoid Arthritis, must be negative for Psoriasis), HLA antigen (often increased in Psoriasis), and, if anemia (low red blood cell count) is present, iron, B12, and folate levels are also tested.

3. Small areas on the patches can be scraped and when looked at under a microscope may show fungal infection.

4. Biopsy (taking a small piece) of the patch is rarely needed for diagnosis and is often done to rule out other possible causes.

Treatment

• Avoid excess sun exposure

• Ultra Violet Light (UVL) -- sunlight, UV-B, and UV-A are effective therapies.  Safer in pregnant women and children than medications.

• Topical corticosteroid creams and ointments of varying strengths (depending on the severity) can be prescribed to reduce the redness and the inflammation.

• Tar shampoos, gels, and baths (for wide-spread disease) are often prescribed.

• Agents to soften the dry skin (keratolytic agents) such as salicylic acid gel can be used in conjunction with other therapies.

• Oatmeal baths can help with itching.

• Soft brushing or scrubbing after baths may help in removing the dead skin.

• In severe cases or with severe and wide spread disease -- agents such as oral corticosteroids, vitamin A derivatives (Etretinate), and chemotherapy drugs such as Methotrexate or Cyclosporin are only for severe and life-threatening cases.

• PUVA is Psoralen (medication) plus UVA but may cause dryness, Cataracts, and increase risk for skin cancer.

• Vitamin D ointment is helpful, but high Calcium levels are potential side effects.

• Avoid harsh brushing, stress, skin trauma, sunburn and Skin Infections (good hygiene).

• Infections of the skin are treated with antibiotic or antifungal medications.

• Desert climates are very good for Psoriasis.

• Drink plenty of fluids.

• Avoid alcohol

• If on therapy, be aware that periodic medical follow-ups and routine blood levels of certain chemicals and parameters are required (especially if on potent medications and treatments).

Prognosis

     Psoriasis is a chronic, lifelong condition that can be controlled with treatment. It can clear for extended periods and relapse. It usually does not adversely affect general health, unless it is neglected.

Complications

• Complications that result from the treatment itself

• Secondary skin infections