Psoriasis is a common and chronic skin condition. The condition is not contagious, cannot be cured nor prevented.

Psoriatic SkinCauses, incidence, and risk factors

The disorder may affect people of any age. In Hong Kong, the incident rate is about 3 out of 1000. Majority is around 30 to 50 years old. It causes skin redness and irritation. Most persons with psoriasis have thick, red skin with flaky, silver-white patches called scales. It can appear suddenly or slowly. In many cases, psoriasis goes away and then flares up again repeatedly over time.

Psoriasis seems to be an inherited disorder. That means it is passed down through families. It is an abnormality in the immune system inducing overgrowth and excess patches of skin. Psoriasis may affect any or all parts of the skin but usually found on the scalp, arms, legs, trunk, nails etc.

The following may trigger an attack of psoriasis or make the condition more difficult to treat:

- Bacteria or viral infections, including strep throat and upper respiratory infections
- Injury to the skin, including cuts, burns, and insect bites
- Some medicines, including anti-malaria drugs, beta-blockers, and lithium
- Stress
- Sunburn
- Too much alcohol

In general, psoriasis may be severe in persons who have a weakened immune system. This may include persons who have:

- Autoimmune Disorders (such as Rheumatoid Arthritis)
- Cancer Chemotherapy

Up to 30% of people with psoriasis may also have arthritis, a condition known as psoriatic arthritis. About 10% of people with psoriasis have visible changes in the nails. Disorders of the fingernails and toenails, including discoloration and pitting of the nails.


PsoriasisPsoriasis most often presented on the elbows, knees, and trunk, but can appear anywhere on the body. For example, there may be flaky patches on the scalp.

The skin patches or dots may be:

- Pink-red in color (like the color of salmon)
- Dry and covered with silver, flaky skin (scales)
- Raised and thick

Additional symptoms may include:

- Joint pain or aching (Psoriatic Arthritis), in serious case joint activity will also be affected. The National Psoriasis Foundation estimates that between 10% to 30% of people with psoriasis also have Psoriatic Arthritis.

- Nail changes, including nail thickening, yellow-brown spots, dents (pits) on the nail surface, and separation of the nail from the base

- Condition may be deteriorated by mood, weak immune system, and changes of weather.


The goal of treatment is to control your symptoms and prevent secondary infections.

Psoriasis that suddenly covers all or most of the body is an emergency that requires a hospital stay. You may receive painkillers, medicines to make you sleepy (sedatives), fluids, and antibiotics to fight any infection.

Mild cases of psoriasis are usually treated at home. Your doctor may recommend any of the following:

- Cortisone cream

- Creams or ointments that contain coal tar or anthralin

- Creams to remove the scaling (usually Salicylic acid or Lactic acid)

- Dandruff shampoos

- Moisturizers

- Prescription medicines containing Vitamin D or Vitamin A (Retinoids), Calcipotriol (Daivonex) and injections such as Infliximab (Remicade)

- Sunlight may help your symptoms go away. Be careful not to get sunburned. Some people may choose to have Phototherapy. Phototherapy is a medical procedure in which your skin is carefully exposed to ultraviolet light.

- Persons with very severe Psoriasis may receive medicines to suppress the body's immune response. These medicines include methotrexate or cyclosporine. (Persons who have Psoriatic Arthritis may also receive these drugs.)



Newer drugs called biologics specifically target the body's immune response, which is thought to play a role in Psoriasis. These drugs are used when other treatments do not work. Biologics approved for the treatment of psoriasis include:

- Adalimumab (Humira) -- only approved for psoriatic arthritis
- Alefacept (Amevive)
- Efalizumab (Raptiva)
- Etanercept (Enbrel)
- Infliximab (Remicade)