Dr. Christina Fitch
BIO 163
14 Nov. 2011

Psoriasis

“Psoriasis is a common skin disease that affects the life cycle of skin cells. Psoriasis causes cells to build up rapidly on the surface of the skin, forming thick silvery scales and itchy, dry, red patches that are sometimes painful” (mayoclinic.com). The word psoriasis was derived from the Greek word psora which means “to itch.” It is neither contagious nor infectious. Though the exact cause of psoriasis is unknown, it is know that the immune system and genetics are major factors in the development of this skin disorder, as well as triggers, which might excite the growth of skin cells. Even though psoriasis only affects about 2-3 percent of the global population, it is one of the most common skin disorders and reason people go to see a dermatologist. Studies show that psoriasis shows up equally among men and women and can appear at any age, but typically between the age of 15 and 35 years. The most common places for psoriasis to appear are the scalp, elbows, knees, and torso, but are not limited to those areas; palms, soles, genitals, nails and although it is rare, the face, anywhere there is skin psoriasis can develop. The psoriasis patches, also known as lesions, general appear symmetrically meaning that if it appears on the left side it will more than likely appear on the right side of the body as well. Not all psoriasis is created equal and can be localized or widespread over the entire body. There are five different types of psoriasis. The different types can appear alone or they sometimes will accompany one another. Each type has its own special characteristics and therapies. While there is no known cure for psoriasis there are a wide variety of treatments to help keep it under control.
Before we get in to much detail of Psoriasis let’s look at the skins normal functions and what it is made of. Our skin is the largest organ of the body and covers about 10 to 22 square feet depending on height and weight. The skin is the boundary between our inner body and the environment of the outside world. It is the first defense against external, foreign substances that can harm us and cause infections. The skin plays a vital role for homeostasis. One of the major roles in conjunction with the brain is to keep our body at a comfortable temperature. The skin of the body also helps us create vitamin D, get rid of waste, stores blood, and detects the sensation of touch. The structure of skin is split into two parts: the epidermis: (the outer most layer that we see) and the dermis (the inner layer). Although the epidermis is very thin it is composed of four layers. The basal layer which is the most superficial layer sits on top of the dermis. The next layer inferior to that is the spinous layer then the granular layer followed by the most out layer called the cornified layer. Keratinocytes (skin cells) begin and continuously divide in the basal layer the cells are then pushed into the next layer (spinous layer). From there they are pushed into the granular layer where keratinocytes quit dividing and the nucleus of the cells dies off. When the keratinocytes from the granular layer are pushed upward to the cornified layer, the cells are now on the outside of the body and are dead. This process generally takes about 21 days. The dermis of the skin sits on a layer of fat and is composed two proteins: collagen and elastin. These allow the skin to be flexible and return to its normal shape. Now that we have looked at the skins basic anatomy and physiology let’s focus on the skin disorder known as Psoriasis. I mentioned earlier that psoriasis affects the cell cycle of the skin and is recognizable by its thick, raised, red lesions that are covered with silvery scales. I also mentioned earlier that there were five types of psoriasis. These five types are plaque-type psoriasis, guttate psoriasis, inverse psoriasis, erythrodermic psoriasis, and pustular psoriasis. Plaque-type psoriasis is the most common amongst the others and occurs in about 80-90 percent of all cases. Plaque is the word given to lesions that are raised and measure approximately 1 centimeter. These types of lesions usually appear oval or round with the border between the infected and non-infected skin very defined. The scales that appear are silvery-white and powdery and can be very thick. The areas that are affected usually appear symmetrically, meaning that if the left knee has lesions then the right knee will have them as well. The scalp can be affected and is extremely itchy. The genitals can be affected, in men more likely than women. Lesions can be small yet can join together to form large plaque. While this next type can develop into plaque-type psoriasis in adults it usually appears in childhood and teenagers. Guattate psoriasis usually develops two to four weeks after tonsillitis or streptococcal infections. These types of lesions appear suddenly after the illness as little raised, scaly bumps about 2-3 millimeters in diameter. They commonly clear up, but it can develop into chronic psoriasis. The next type of psoriasis is as unique as the first two. Inverse psoriasis is exclusive in the way that it actually doesn’t have any scales at all covering the lesions. The skin involved with inverse psoriasis is moist and smooth with a salmon color. This type generally only appears in the folds of the skin such as the armpits, underneath the breast, groin, and the perianal location. It can particularly be irritating to have this type because it is often tender, raw, and can be very itchy. With these being the affects its makes it difficult to scratch in public because of the location of these lesions and can become extremely uncomfortable. Inverse psoriasis is often paired with the first type I described, plaque-type psoriasis. The following two types of psoriasis can be severe cases and can even cause the individual to be hospitalized. Erythrodermic psoriasis can cover almost the entire body or the entire body, including the eyelids, lining of the mouth, and inside of the nose with scaly lesions. “Erythrodermic psoriasis usually appears in one of two forms. First, a chronic, long-standing plaque-type psoriasis may gradually progress so that increasing areas of skin become involved. Second, erythrodermic psoriasis can occur in people with unstable psoriasis and can be triggered by several factors, including illness, emotional stress, [and] alcoholism” (Langley 14). In some cases the scales are not always dominant, widespread areas of raw, red, itchy, swollen skin is present, sometimes causing small blisters (pustular) to fill with pus and ooze from the lesions. People with erythrodermic psoriasis are often sick and are very prone to skin infections; they also have trouble maintaining normal body temperature and proper levels of fluid. The final type of is pustular psoriasis and appears in the form of small blister-like areas with non-infectious pus on the skin. These small blisters are usually surrounded by reddened skin. While the most common form of pustular psoriasis is localized to the hands and feet it can also be generalized over the entire body. People with the generalized form of pustular psoriasis are often are very ill and require hospitalized until the psoriasis is under control.
“Psoriasis is a complex disease that is caused by several factors. Although there is no known single cause for psoriasis , it is clear that genetics, the skin cells (keratinocytes), environmental factors and the immune system play central roles in causing this disease” (R. Langley 23). The most critical of all these roles is the immune system. When our immune system functions normally it is able to protect us against bacteria, viruses, antigens, and even cancer. The immune system and psoriasis wasn’t linked until the improvement of psoriasis was noted when patients would take the drug cyclosporine. This is the most significant discovery in the study of psoriasis and has led to more effective medications and treatment for people suffering from psoriasis. Though the immune system is a critical role in the development of psoriasis it is likely that that this skin disorder was inherited. There is 10-20 percent chance that if a parent has psoriasis the kid will end up with it as well. That percentage rises to 50 percent if both parents have psoriasis. Researchers are still unaware of what genes contribute. Genetics definitely plays a role, but patients with psoriasis have noticed that other external and internal factors contribute to flare-ups as well. Factors include: climate, infections, medications, stress, and skin injuries.
When going to the doctor to be examined proper diagnoses is required to be able to receive the best treatment for the patient’s condition. Often people confuse psoriasis with eczema. In most cases the doctor will be able to give the correct diagnoses with just a physical examination and a few questions such as family history, and the location of the patches. In 15-30 percent of the time psoriasis is accompanied with psoriatic arthritis. Although it does not usually occur with the first signs of psoriasis lesions it is possible, but generally develops after years of having the first sign of psoriasis on the skin. Signs that may suggest psoriatic arthritis are stiffness, swelling and tenderness of joins, redness and tenderness of the eyes, and inflammation of the urethra (narrow tube that empties the bladder). Being diagnosed with psoriasis not only affects the body physically, but mentally as well. Having psoriasis can induce low-self-esteem and can impair relationships in the personal life and work. The greater the severity of the disease generally will produce a greater negative impact. All patients diagnosed with psoriasis are encouraged to talk about their feeling, give treatment a chance, seek support if needed, and stay positive all together.
There are four types of main treatment and some patients will only use one type while other will use a combination of them. These treatments include tropical treatment, phototherapy, systemic therapy, and biologics. Each patient’s treatment will be individualized because what works for one person may not necessarily work for another. The type of psoriasis, extent of the disease, areas affected, lifestyle, other health problems, social and sexual impact are just a few of the several factors that go in to making each specific treatment plan for every patient. Tropical treatments are an important tool when it comes to a mild form of psoriasis. It helps keep the lesions moist which slow down the dehydration of the skin causing less itching and flaking. Tropical treatments include creams, ointments, lotions, gels and aerosols. In the moisturizers are steroids that reduce the skins inflammation and salicylic acid that aid in the reduction of scaling. Natural sunlight is a known benefactor for helping. UV (ultraviolet) rays are what contribute to that factor. That’s why phototherapy, also known as light therapy, is highly effective when it come to the treatment of psoriasis. Using UVB (B= burning) rays is the most beneficial and can be used alone are with other treatments. The next treatment goes directly in to circulatory system and is used with patients that have moderate to severe psoriasis. “Systemic drugs are medications that are given either orally (pills) or as injections just below the skin (subcutaneous) or into the muscle (intramuscular)” (R. G. Langley 122). This type of treatment is always combined with tropical and phototherapies. Biologic therapy is the newest type of treatment and is rapidly growing. With the new understanding that the immune system plays the vital role in the development of psoriasis biotechnology companies are creating drugs that target these abnormalities. “Biologics are different because they are made from living cells, such as viruses, animal cells and human cell. Biologic drugs have natural counterparts, such as protiens, enzymes, anitbodies or nucleic acids” (R. Langley 138).
In conclusion psoriasis is one of the most annoying and frustrating skin disorder there is. With its itchy, red, raised patches on the skin and the possibility of it being widespread it is not something that anyone would care to handle and take care of on a daily basis. Psoriasis is a life-long disease that can only be controlled with proper treatment. Even though it may go away at some point it is sure to arise again. There is no way to prevent the development of psoriasis, but with the ever increasing understanding of psoriasis there are new medications and therapies. Hopefully in the near future there will be a way to easily control this still highly misunderstood disease.

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[ 1 ]. The condition in which the body’s internal environment remains relatively constant, with in physiological limits (Tortora and Derrickson).
[ 2 ]. A drug to prevent the rejection of an organ transplant by suppressing the immune system.
[ 3 ]. A segment of DNA located in a definite position on a particular chromosome (Tortora and Derrickson).