Causes of Psoriasis

Psoriasis is a chronic skin condition that is estimated to affect between one and three percent of the world\’s population. Individuals who suffer from psoriasis will experience periodic flareups of well defined red patches that appear to be covered by a silvery flaky scale. There are several variations but the most common type is chronic plaque psoriasis.

The exact cause of psoriasis is currently unknown but researchers believe that there is a combination of several factors that contribute to the development of the disease. And, while they continue to search for a cure, researchers have identified several triggers, or factors which initiate a flareup.

Psoriasis is characterized by skin cells that multiply up to 10 times faster than normal. In a normal circumstance skin cells develop in the lower layers and as the upper layers of the surface die and flake off, the new skin rises to the surface. When an individual experiences the symptoms of psoriasis individual patches of skin will go through this a cycle much more quickly than normal. This results in raised red areas covered with white scale. Psoriasis will typically happen on the knees, elbows and scalp; it can also affect the palms and soles of the feet as well as the torso.

Current research has found nine gene mutations that can be involved in causing psoriasis. One of these mutations is on chromosome number six and appears to be a major factor that leads to the development of the disease. Mutations on genes will cause certain cells to function differently because genes control the way in which the body functions. In individuals who suffer from psoriasis these mutations seem to largely affect the T-helper cells, part of an individual\’s immune system.

These gene mutations, which affect the immune system, also affects the white blood cells which produce antibodies to foreign invaders. These white blood cells will also produce chemicals that help the body to shield and fight infections. But, with psoriasis, these special white blood cells become overactive.

T-cells attack the skin and set off a cascade of events that makes the skin cells multiply so fast that they stack up on the surface. The normal lifecycle of a skin cell ranges around 30 days but in plaque psoriasis the skin goes through the entire process in three to six days.

Not everyone who has these mutations will get psoriasis and there are other forms that people can develop without having any gene mutations. There are certain environmental triggers that can play a role in causing psoriasis in people.

Sometimes an injury to the skin can cause the formation of a psoriasis patch. This same type of patch can also occur in individuals who suffer from eczema. This could take between two and six weeks to develop after an injury and that injury can be as mild as an abrasion or even increased friction from clothing on the skin. Individuals can also develop psoriasis after a sunburn, viral rash or drug rash.

Other triggers can include emotional stress or streptococcal infection. As many as 80 percent of individuals who have flareups report a recent emotional trauma at a new job or the death of a loved one. Researchers believe that these external stressors serve as a trigger because they negatively impact the immune function of the individual.

Certain medications, such as blood pressure medication and beta-blockers as well as anti-malarial medications, can aggravate psoriasis and causes flareups. Weather is another strong trigger. Individuals who are exposed to cold and dry weather will have a flareup while hot, damp or sunny weather makes the psoriasis symptoms better.

The most common infection that will trigger a psoriasis flareup is streptococcal. This bacteria commonly causes tonsillitis, sinusitis or strep throat. The human immunodeficiency virus (HIV) is also associated with the development of psoriasis because of the impact it has on the individual\’s immune system.

Other individuals find that psoriasis flareups are triggered when they have low levels of calcium or have not been exposed to enough sunlight to develop adequate levels of vitamin D. The body is able to produce or manufacture vitamin D on its own when exposed to the sun but researchers have also developed supplements which can be used to treat psoriasis and have been successful.

Other drugs which are known to either worsen psoriasis or induce a flareup include ACE inhibitors, lithium, and to send and corticosteroids such as prednisone or solumedrol. While corticosteroids can actually produce a dramatic improvement in psoriasis, abruptly stopping the drug or rapidly tapering off can cause a large flareup.

Researchers continue to search for a definitive cause for psoriasis believing that once a cause is identified better treatment modalities will be developed as well as the potential to develop preventative measures for those who do not have gene mutations that cause an impairment of the immune system.

RESOURCES

PubMed Health: Psoriasis
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001470/

MayoClinic: Psoriasis
http://www.mayoclinic.com/health/psoriasis/DS00193

American Academy of Dermatology: Psoriasis, Who Gets it and causes
http://www.aad.org/skin-conditions/dermatology-a-to-z/psoriasis/who-gets-causes/psoriasis-who-gets-and-causes