Psoriasis – Skin Cells Growing Too Fast

Danger level: Medium

What is it?

Psoriasis is a skin disorder causing red scaly patches on the skin.

Who gets it?

In the United States, 2-2.6% of the white population and 1.3% of African Americans have psoriasis, with about 200,000 new cases each year. Worldwide it affects about 1-5% of the population.

It’s more common in Caucasians, and a little more common in women than in men. It usually starts around age 20, but can start at any age.

In about 40% of people with psoriasis there is also a family history of psoriasis, since it probably has a genetic cause.

What causes it?

Our skin has many layers. In normal skin, new cells form all the time and move up the skin layers until they reach the most superficial layer. When they do, these cells die and then shed. This process takes between 28-30 days.

In psoriasis, new cells grow and move up the layers much faster: it takes them 3-4 days. The buildup of cells on the skin’s surface forms the scales and patches in the disease.


A piece of skin showing its layers. In psoriasis, skin cells move up the layers too fast, accumulating on the surface.

What causes this? One of the theories around psoriasis claims that it is an autoimmune disease. This means that the body’s immune system, which is usually meant to fight infections, also fights the body’s skin cells. (We covered other types of autoimmune diseases here before, such as Graves disease, vitiligo, lupus, and others). This results in an inflammation of the skin and the fast renewal of skin cells.

Outbreaks of psoriasis are caused by known triggers:

  1. An injury to the skin
  2. Emotional stress
  3. Infections, such as a throat infection
  4. Cold weather
  5. Smoking
  6. Heavy alcohol consumption
  7. Some drugs – Such as lithium (for bipolar disorder), beta blockers (for high blood pressure), drugs against malaria and others.

How does it feel?

The symptoms in psoriasis include:

  1. Areas of skin that are dry or red. They are usually also covered with silvery-white scales, and sometimes with raised edges.Psoriasis
    The skin in psoriasis. Photo by Marnanel.
  2. These skin areas appear thick, but they bleed easily if the scales are picked up or rubbed off.
  3. Itching
  4. Nail abnormalities: Such as pitting (indentations on the nail), a change of color, or crumbly nails.
  5. Sometimes psoriasis can also affect the joints, causing inflammation in them, which can cause them to swell and be stiff and painful.

The areas of the skin that are usually most involved in the disease are the scalp, the back of the elbows and knees, the buttocks, and the penis. The disease can affect just a few spots of skin or can cover large sk

in areas.

Although not life-threatening, psoriasis can greatly affect a person’s self-image.

How is it discovered?

Usually the doctor can decide that a person has psoriasis by looking at the skin. It some cases, they may perform a skin biopsy, in which a piece of skin is cut and looked at under the microscope, to make certain that it’s indeed psoriasis and not some other similar disease.

How is it treated?

There is no cure for psoriasis, but treatments are available to interrupt the cycle of fast skin cell renewal and to remove the scaly skin patches.

There are 3 types of treatment for psoriasis:

  1. Medicines applied to the skin – This includes creams and ointments you rub on your skin. Usually these are used for a disease which is mild or moderate. More severe cases require other methods.
    Creams used here include steroid creams, vitamin D creams, retinoid creams and others.
  2. Light therapy – Ultraviolet light is the light produced by the sun, and which can also be produced artificially by special machines. It’s been found that exposure to ultraviolet light slows the skin turnover in the disease and improves the scaling and inflammation of the skin. It’s important to do this under a doctor’s guidance, since too much exposure to ultraviolet light can be dangerous.
  3. Drugs – There are some medications which can be taken by mouth to help treat psoriasis. They are usually given in severe cases. These include retinoids, methotrexate, cyclosporin and others.

What happens after treatment?

As mentioned above, there is no cure for psoriasis, and it lasts for life. Treatment, if taken, can greatly reduce the symptoms of the disease, even in severe cases.

The bottom line – How do I avoid it?

There is no way to prevent psoriasis, but if you have it, there are some things you can do to reduce the activity of the disease:

  1. Keeping the skin moist
  2. Avoiding cold, dry climates – As mentioned above, cold weather makes the disease worse.
  3. Avoiding scratching the skin or skin injuries
  4. Avoiding stress
  5. Avoiding infections – Such as throat infections
  6. Avoid medications which can worsen the disease (see above)
  7. Limiting alcohol – To no more than 2 drinks a day for men and 1 for women.
  8. Stopping smoking

The American Academy of Dermatology and the National Psoriasis Foundation have joined together to form the Stop Hiding from Psoriasis public education campaign.You can visit their website at and watch this video, featuring singer LeAnn Rimes.

You can also visit these blogs about psoriasis: Scratch that darn itch, The psoriasis blog.
Category : Skin