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

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 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 and 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.

The classic symptoms of psoriasis includes swollen, red patches of skin, or lesions, that are covered with loose, silvery scales. Psoriasis most frequently occurs on the knees and elbows, although it can appear on the skin anywhere throughout the body. The most common symptoms of psoriasis include:

• Plaques: Plaques are elevated or swollen areas of skin. They can vary in size from one centimeter to several centimeters. Some people experience only a few plaques at a time, while others develop many plaques all at once. Plaques are usually oval in shape but they may be irregularly shaped as well. Occasionally, several smaller plaques may merge together to form one large affected area. Plaques sometimes have an area around them that looks like a halo or ring. This is known as the Ring of Woronoff. Plaques can occur anywhere, but commonly they occur on the knees, elbows, scalp, hands, feet, or lower back.
• Bleeding: The skin in the affected area may become so dry that is begins to crack and bleed. In addition, tiny areas of bleeding may develop when skin scales are picked or scraped off. This is known as Auspitz’s sign.
• Scales: Psoriasis is characterized by loose scales that cover the affected area. These scales are typically dry, thin, and silvery-white. The thickness of the scales may vary from a mild case to a thick crust of scales. When the scales are removed, the skin underneath is usually red, smooth, and glossy.
• Itching: Psoriasis lesions or plaques commonly itch, especially when they develop suddenly, or when they occur in flexural areas of the body such as under the breasts or the buttocks.
• Redness: Skin that is affected by psoriasis is typically a very distinctive salmon-red color. Occasionally, when psoriasis occurs on the legs, the skin may appear to have a blue tint.
• Symmetry: Psoriatic plaques or lesions tend to appear on both sides of the body in the same places. This is known as symmetry. For instance, psoriasis will usually develop on both knees or both elbows at the same time.
• Nail Disorders: Studies show that approximately fifty percent of people with psoriasis also develop nail disorders. Symptoms of nail disorders include pitting; yellowish discoloration; a buildup of skin debris under the nails; or a separation of the end of the nail from the nail bed.
• Scalp: Some people who develop psoriasis will have dry, scaly skin or crusted plaque areas on their scalp. Scalp psoriasis is often confused with seborrheic dermatitis. However, the scales of scalp psoriasis are silvery and dry compared to the yellowish, greasy scales of seborrheic dermatitis.
• Other Symptoms: Psoriasis most common affects the arms, leg, back, and scalp however the condition can actually occur on any body part. Psoriasis can also be found on the genitals or buttocks, under the breasts, or under the arms, causing extreme sensitivity, itching, and burning.

Symptoms in Children

Plaque psoriasis looks slightly different in children compared to adults. Children tend to develop plaques that are not quite as thick and scaly as those found on adults. Psoriasis can develop in the diaper region in young babies and toddlers, and in the folds of skin children. In addition, psoriasis occurs more commonly on the face in children than it does in adults.

There are several types of psoriasis, and each of these is associated with its own unique set of symptoms. The symptoms for each type of psoriasis may vary in duration and severity.

• Plaque Psoriasis: Plaque psoriasis is the most common type of psoriasis. It is characterized by skin lesions that are red at the base and covered by silvery scales. Approximately ninety percent of people who suffer from psoriasis have plaque psoriasis.
• Guttate Psoriasis: Guttate psoriasis is thought to be triggered by an upper respiratory infection such as strep throat. The condition causes small, drop-shaped lesions that typically appear on the trunk, limbs, and scalp. Guttate psoriasis often clears up only to recur as plaque psoriasis.
• Pustular Psoriasis: In rare cases, the patches of dry, scaly skin can crack and have pus on top of them. These blisters of noninfectious pus are characteristic of pustular psoriasis. This condition may be triggered by an infection, stress, or a reaction to certain medications or chemicals.
• Inverse Psoriasis: Inverse psoriasis develops as the result of friction of excessive rubbing on the skin. Smooth, red patches of skin generally occur in the folds of the skin near the genitals, under the breasts, or in the armpits. Sweating may worsen the symptoms of inverse psoriasis.
• Erythrodermic Psoriasis: A severe skin reaction to a sunburn or to certain medications may cause the development of erythrodermic psoriasis. This type of psoriasis is characterized by widespread reddening and scaling of the skin.
• Psoriatic Arthritis: Psoriatic arthritis is characterized by inflammation and pain in the joints as well as on the skin.