Psoriasis is a disease which affects the skin and joints. It commonly causes red scaly patches to appear on the skin. The scaly patches caused by psoriasis, called psoriatic plaques, are areas of inflammation and excessive skin production. Skin rapidly accumulates at these sites and takes a silvery-white appearance.Plaques frequently occur on the skin of the elbows and knees, but can affect any area including the scalp and genitals.

Psoriasis is an inflammatory skin disease in which skin cells replicate at an extremely rapid rate. New skin cells are produced about eight times faster than normal--over several days instead of a month--but the rate at which old cells slough off is unchanged. This causes cells to build up on the skin's surface, forming thick patches, or plaques, of red sores (lesions) covered with flaky, silvery-white dead skin cells (scales).

The disorder is a chronic recurring condition which varies in severity from minor localised patches to complete body coverage. Fingernails and toenails are frequently affected (psoriatic nail dystrophy) - and can be seen as an isolated finding. Psoriasis can also cause inflammation of the joints, which is known as psoriatic arthritis.

The cause of psoriasis is not known, but it is believed to have a genetic component. Several factors are thought to aggravate psoriasis. These include stress, excessive alcohol consumption, and smoking. Individuals with psoriasis may suffer from depression and loss of self-esteem. As such, quality of life is an important factor in evaluating the severity of the disease. Certain medicines, including lithium salt and beta blockers, have been reported to trigger or aggravate the disease.

There are two main hypotheses about the process that occurs in the development of the disease. The first considers psoriasis as primarily a disorder of excessive growth and reproduction of skin cells. The problem is simply seen as a fault of the epidermis and its keratinocytes.The second hypothesis sees the disease as being an immune-mediated disorder in which the excessive reproduction of skin cells is secondary to factors produced by the immune system. T cells (which normally help protect the body against infection) become active, migrate to the dermis and trigger the release of cytokines (tumor necrosis factor-alpha TNF, in particular) which cause inflammation and the rapid production of skin cells. It is not known what initiates the activation of the T cells.The immune-mediated model of psoriasis has been supported by the observation that immunosuppressant medications can clear psoriasis plaques.

Plaque psoriasis (psoriasis vulgaris) is the most common form of psoriasis. It affects 80 to 90% of people with psoriasis. Plaque psoriasis typically appears as raised areas of inflamed skin covered with silvery white scaly skin. These areas are called plaques.

Flexural psoriasis (inverse psoriasis) appears as smooth inflamed patches of skin. It occurs in skin folds, particularly around the genitals (between the thigh and groin), the armpits, under an overweight stomach (pannus), and under the breasts (inframammary fold). It is aggravated by friction and sweat, and is vulnerable to fungal infections.

Guttate psoriasis is characterized by numerous small oval (teardrop-shaped) spots. These numerous spots of psoriasis appear over large areas of the body, such as the trunk, limbs, and scalp. Guttate psoriasis is associated with streptococcal throat infection

Pustular psoriasis appears as raised bumps that are filled with non-infectious pus (pustules). The skin under and surrounding pustules is red and tender. Pustular psoriasis can be localised, commonly to the hands and feet , or generalised with widespread patches occurring randomly on any part of the body.

Nail psoriasis produces a variety of changes in the appearance of finger and toe nails. These changes include discolouring under the nail plate, pitting of the nails, lines going across the nails, thickening of the skin under the nail, and the loosening (onycholysis) and crumbling of the nail.

Psoriatic arthritis involves joint and connective tissue inflammation. Psoriatic arthritis can affect any joint but is most common in the joints of the fingers and toes. This can result in a sausage-shaped swelling of the fingers and toes known as dactylitis. Psoriatic arthritis can also affect the hips, knees and spine (spondylitis). About 10-15% of people who have psoriasis also have psoriatic arthritis.

Erythrodermic psoriasis involves the widespread inflammation and exfoliation of the skin over most of the body surface. It may be accompanied by severe itching, swelling and pain. It is often the result of an exacerbation of unstable plaque psoriasis, particularly following the abrupt withdrawal of systemic treatment. This form of psoriasis can be fatal, as the extreme inflammation and exfoliation disrupt the body's ability to regulate temperature and for the skin to perform barrier functions.

A diagnosis of psoriasis is usually based on the appearance of the skin. There are no special blood tests or diagnostic procedures for psoriasis. Sometimes a skin biopsy, or scraping, may be needed to rule out other disorders and to confirm the diagnosis. Skin from a biopsy will show clubbed pegs if positive for psoriasis. Another sign of psoriasis is that when the plaques are scraped, one can see pinpoint bleeding from the skin below (Auspitz's sign).

There can be substantial variation between individuals in the effectiveness of specific psoriasis treatments. Because of this, dermatologists often use a trial-and-error approach to finding the most appropriate treatment for their patient. The decision to employ a particular treatment is based on the type of psoriasis, its location, extent and severity. The patients age, gender, quality of life, comorbidities, and attitude toward risks associated with the treatment are also taken into consideration.

Medications with the least potential for adverse reactions are preferentially employed. As a first step, medicated ointments or creams are applied to the skin. If topical treatment fails to achieve the desired goal then the next step would be to expose the skin to ultraviolet (UV) radiation. This type of treatment is called phototherapy. The third step involves the use of medications which are taken internally by pill or injection : systemic treatment.Over time, psoriasis can become resistant to a specific therapy. Treatments may be periodically changed to prevent resistance developing (tachyphylaxis) and to reduce the chance of adverse reactions occurring: treatment rotation.

Salicylic acidKeratolytic agents, weak antifungals, antibacterial agentsRemove accumulated scale, allow topical agents to pass throughAE: irritation, salicylism (N&V, tinnitus)

Coal TarPrefered for limited or scalp psoriasisCan be effective in widespread psoriasisAntimitotic, anti-pruriticNo quick onset but longer remissionOften combined with SA, UV light therapy2 types: Crude coal tar and Liquor picis carbonis

May restore normal epidermal proliferation and keratinizationUseful in thick plaque psoriasisCommonly used with SA2 treatment approach: long contact and short contactStains clothes, irritating to normal skin

Anti-inflammatory, immunosuppressiveQuick onset than coal tar and dithranolTachyphylaxis can occurHigh potent agents used in severe cases, thick plaquesAE local and systemicShould not be stopped abruptly rebound psoriasis

UVA, UVB, PUVAUVB preferedAdministered by lamp, sunlight exposure alone or in combo with another topical agentPUVA (methoxsalen) given PO 2 hours before UVA or lotion applied 30mins before exposureAE: itch, edema

ImmunomodulatorsCyclosporin, methotrexate commonly used

Antibiotics in case of secondary bacterial infections

Systemic agents are generally recommended for patients with moderate-to-severe disease. Moderate disease is defined as greater than 5% body-surface area involvement; severe disease is defined by greater than 10%

ASSESSMENTFocuses on the appearance of the normal skin, the appearance of the skin lesions, and how the patient is coping with the psoriatic skin condition.The nurse assess the impact of the disease on the patient and the coping strategies used for conducting normal activities and interaction with family and friends.

PROMOTING UNDERSTANDINGThe nurse explain with sensitivity that although there is no cure for psoriasis and life time management is necessary ,the condition can usually be controlled.The pathophysiology of psoriasis is reviewed ,as are the factors that provoke it irritation or injury to the skin (ex-cut, abrasion ,sunburn), current illness (ex- pharyngeal streptococcal infection), and emotional stress.

Reviewing and explaining the treatment regimen are essential to ensure compliance.For ex- if the patient has a mild condition confined to localized areas ,such as the elbows or knees ,application of an emollient to maintain softness and minimize scaling may be all that is required.INCREASING SKIN INTEGRITYTo avoid injuring the skin ,the patient is advised not to pick at or scratch the affected areas.Measures to prevent dry skin are encouraged because dry skin worsens psoriasis.

Too frequent washing produces more soreness and scaling.Water should be warm ,not hot ,and the skin should be dried y patting with a towel rather than rubbing.A bath oil or emollient cleansing agent can comfort sore and scaling skin.IMPROVING SELF- CONCEPT AND BODY IMAGEA therapeutic relationship between health care professional and the patient with psoriasis includes education and support.

Introducing the patient to successful coping strategies used by other with psoriasis .MONITORING AND MANAGING POTENTIAL COMPLICATIONSThe diagnosis of psoriasis ,especially when it is accompanied by the complication of arthritis ,is usually difficult to make.The patient require education about the care and treatment of the involved joints and the need for compliance with therapy.

Psoriasis is a lifelong condition.There is currently no cure but various treatments can help to control the symptoms. Many of the most effective agents used to treat severe psoriasis carry an increased risk of significant morbidity including skin cancers, lymphoma and liver disease. Psoriasis does get worse over time but it is not possible to predict who will go on to develop extensive psoriasis or those in whom the disease may appear to vanish. Individuals will often experience flares and remissions throughout their lives. Controlling the signs and symptoms typically requires lifelong therapy.