January 2008
Causes of Psoriasis
Psoriasis is not contagious-it cannot be passed from person to person. However, the exact cause of psoriasis is not known. Most health experts agree that genetic factors play some role in the development of the condition. Approximately one-third of the people who are diagnosed with psoriasis have one or more family members with the condition. Yet it is unclear if genetic factors alone determine the propensity for psoriasis. Many doctors also believe that other factors, such as certain immune response and environmental conditions may play a role in the development of the disease. Other factors that may cause or aggravate psoriasis include climate, skin injuries, stress, infections, or a reaction to certain medications.
Genetics
About one third of patients with psoriasis have a family member who has also been diagnosed with the condition. Thus, those with a family history of psoriasis have an increased chance of developing the disease themselves. When both parents have psoriasis, the child’s risk of developing the disease may increase as much as fifty percent. Many researchers now believe that there are certain genes that are linked to the development of psoriasis.
A recent British study found that a small region of what is known as Chromosome 6 might contain at least one gene that indicates psoriasis susceptibility. Other genes may also be involved in the development of the disease, and there is a great deal of research currently underway to understand more about the role that genetics plays in psoriasis.
Immune Responses to Psoriasis
There is also a great deal of evidence to indicate that psoriasis may result from a disorder in the immune system. Our immune system is responsible for the production of white blood cells that protect our bodies from infection. For those with psoriasis, some for the white blood cells (the T cells) abnormally trigger inflammation in the skin. These T cells are also responsible for the excessively rapid skin growth that leads to the development of thickened patches on the outer surface of the skin. Another indicator that the immune system plays a role in psoriasis is that the disease tends to respond to medications that suppress the immune system.
Environmental Factors
The role of environmental factors in the development of psoriasis is not clear. However, there are certain environmental conditions that tend to cause or aggravate a psoriatic flare up. These factors include harsh weather conditions, excessive exposure to the sun, and certain medications.
Climate: Patients who have psoriasis tend to have very dry sensitive skin. This skin is easily irritated by harsh weather conditions such as the cold, dry weather of winter. Most people with psoriasis experience a worsening of symptoms in the winter months, and an improvement in the summer months when there is more hot weather, sunlight, and humidity.
Sunlight: Sunlight is generally considered beneficial to those with psoriasis. So much so that ultraviolet light is often prescribed as a treatment for flare ups. However, some psoriasis sufferers find that strong sunlight aggravates their symptoms. In addition, those with psoriasis tend to have sensitive skin that may be excessively irritated by bad sunburn.
Certain medications: A number of medications have been found to cause or aggravate the symptoms of psoriasis. Examples of these medications include NSAIDS (medications such as ibuprofen, or naproxen that are used to relieve inflammation), beta-blockers (drugs used to control high blood pressure), Lithium (a medication used to treat depression), and anti-malarial medications. Be sure to tell your health care provider that you have psoriasis before one of these medications are prescribed for you.
Other Psoriasis Factors
Other factors that may cause or aggravate the symptoms of psoriasis include skin injuries, stress, infections, smoking, alcohol consumption, and hormonal changes.
Skin Injury: An injury to the skin can cause the development of psoriasis patches to form anywhere on the body, regardless of the actual site of the injury. A skin infection, skin inflammation, a nail injury, or even excessive scratching can trigger psoriasis.
Stress & Anxiety: Many people experience a flare up or worsening of psoriasis symptoms when they are under an increased amount of emotional stress.
Infection: Infections, such as the streptococcal infection that causes strep throat, can cause psoriasis to appear suddenly. This type of bacterial infection is linked to a form of psoriasis known as guttate psoriasis in which small, red, tear drop shaped marks appear on the skin.
Smoking: Cigarette smokers have an increased risk of developing chronic plaque psoriasis, and from suffering from symptoms that are last longer and are more severe than non-smokers.
Alcohol: Alcohol is considered a risk factor for the development of psoriasis, particularly in young to middle-aged males.
Hormonal Changes: Psoriasis has also been known to fluctuate with a person’s hormonal changes. The frequency of flare ups tends to peak during puberty and menopause. Psoriasis symptoms are also alleviated during pregnancy, and then aggravate again in the postpartum period.