Psoriasis is a chronic, noninfectious, inflammatory disease of the skin in which the production of epidermal cells occurs at a rate that is about six to nine times faster than normal. Onset may occur at any age but is most common between the ages of 15 and 50 years. Main sites of the body affected are the scalp, areas over the elbows and knees, lower part of the back, and genitalia. Bilateral symmetry often exists. Psoriasis may be associate with asymmetric rheumatoid factor-negative arthritis of multiple joints. An exfoliative psoriatic state may develop in which the disease progresses to involve the total body surface (erythrodermic psoriatic state).
PATHOPHYSIOLOGY
The basal skin cells divide too quickly, and the newly formed cells become evident as profuse scales or plaques of epidermal tissue. Psoriatic cells may travel from the basal cell layer of the epidermis to the stratum corneum (skin surface) and be cast off in 3 to 4 days, in sharp contrast to the normal 26 to 28 days. Because of the rapid cell passage, the normal events of cell maturation and growth cannot take place and the normal protective layers of the skin cannot form. There appears to be a hereditary defect that causes overproduction of keratin. The primary defect is unknown. Periods of emotional stress and anxiety aggravate the condition, and trauma, infections, and seasonal and hormonal changes are trigger factors.
CLINICAL MANIFESTATIONS
Symptoms range from a cosmetic annoyance to a physically disabling and disfiguring affliction.
• Lesions appear as red, raised patches of skin covered with silvery scales.
• If scales are scraped away, the dark-red base of lesion is exposed, with multiple bleeding points.
• Patches are dry and may or may not itch.
• The condition may involve nail pitting, discoloration, crumbling beneath the free edges, and separation of the nail plate.
• If psoriasis occurs on the palms and soles, pustular lesions may develop.
• In erythrodermic psoriasis, the patient is acutely ill, with fever, chills, and an electrolyte imbalance.
PSYCHOLOGICAL CONSIDERATIONS
• Psoriasis may cause despair and frustration; observers may stare, comment, ask embarrassing questions, or even avoid the person.
• The condition can eventually exhaust resources, interfere with work, and make life miserable in general.
• Teenagers are especially vulnerable to its psychological effects.
• Psoriasis can cause family disruption because of time-consuming treatments, messy salves, and constant shedding of scales.
ASSESSMENT AND DIAGNOSTIC METHODS
• Classic plaque-type lesions (change histologically progressing from early to chronic plaques)
• Signs of nail and scalp involvement and positive family history
