Cause of Psoriasis
Currently there's no full understanding for the cause of psoriasis, but a few theories exist. The cause includes genetics, lifestyle, HIV, medications. It is not purely a skin disorder and can have a negative impact on many organ systems. Psoriasis has been associated with an increased risk of certain cancers, cardiovascular disease, and other immune-mediated disorders such as Crohn's disease and ulcerative colitis. It is generally considered a genetic disease, thought to be triggered or influenced by environmental factors. Psoriasis develops when the immune system mistakes a normal skin cell for a pathogen, and sends out faulty signals that cause overproduction of new skin cells. It is not contagious. Oxidative stress, stress, and withdrawal of a systemic corticosteroid have each been suggested as a trigger for psoriasis. Injury to the skin can trigger local psoriatic skin changes known as the Koebner phenomenon.
Diagnosis of Psoriasis
Doctors usually diagnose the psoriasis according to the appearance of the skin. There are several typical characteristics for psoriasis such as scaly, erythematous plaques, papules, or patches of skin that may lead to pain and itch. No special blood tests or diagnostic procedures are needed for the diagnosis. If there's uncertainty for the clinical diagnosis, a skin biopsy can be performed to confirm the diagnosis. The biopsy will show clubbed epidermal projections that interdigitate with dermis on microscopy.
Classification of Psoriasis
Psoriasis is classified as a papulosquamous disorder and is most commonly subdivided into different categories according to histological characteristics. The five main types of psoriasis are plaque, guttate, inverse, pustular, and erythrodermic. Plaque psoriasis is the most common form, which typically manifests as red and white scaly patches on the top layer of the skin. At the plaques the skin cells will accumulate gradually and quickly, then create a silvery-white appearance. Plaques can affect any area of the body such as the scalp, palms of hands, and soles of feet, and genitals, but most commonly on the skin of the elbows and knees. Compare to eczema, psoriasis is more likely to be found on the outer side of the joint. Fingernails and toenails are frequently affected (psoriatic nail dystrophy) and can be seen as an isolated sign. In addition, psoriatic arthritis affects over 30% of individuals with psoriasis.
Prognosis of Psoriasis
Psoriasis has a negative effect on the quality of life for both the patient and the individual's family members. Basing on the severity and location of outbreaks, patients would experience significant physical discomfort and disability. Itch and pain interfere with basic functions, such as self-care and sleep. For those with plaques located on their hands and feet, there can be many difficulties in sporting activities, certain occupations, and caring for family members. Plaques on the scalp can be particularly embarrassing, as flaky plaque in the hair can be mistaken for dandruff.
Individuals with psoriasis may feel self-conscious about their appearance and have a poor self-image that stems from fear of public rejection and psychosexual concerns. Psoriasis has been associated with low self-esteem and depression is more common among those with the condition. People with psoriasis often feel prejudiced against due to the commonly held incorrect belief that psoriasis is contagious. Psychological distress can lead to significant depression and social isolation; a high rate of thoughts about suicide has been associated with psoriasis. Many tools exist to measure the quality of life of patients with psoriasis and other dermatological disorders. Clinical research has indicated individuals often experience a diminished quality of life. Children with psoriasis may encounter bullying.