PSORIASIS
Psoriasis is a common, chronic, disfiguring, inflammatory and proliferative condition of the skin; in which both genetic and environmental influences play a critical role characterized by red, scaly, sharply demarcated thick plaques of various sizes, particularly over outer surfaces of the limbs and scalp.
Psoriasis is generally thought to be a genetic disease which is triggered by environmental factors. In twin studies, identical twins are three times more likely to both be affected compared to non-identical twins; this suggests that genetic factors predispose to psoriasis. Symptoms often worsen during winter and with certain medications such as painkillers lithium, Antimalarials, antihypertensives and steroids. Infections and psychological stress may also play a role. Psoriasis is not contagious. The underlying mechanism involves the immune system reacting to skin cells. Diagnosis is typically based on the signs and symptoms.
Patients give H/O prominent itchy, red areas with increased skin scaling and peeling.New lesions appearing at sites of injury/trauma to the skin. Actual clearance of lesions following trauma to the skin can also be seen. Exacerbation in winter, improvement in summer. Significant joint pain, stiffness, deformity in 10-20%.
Morphology
Classical Lesion consists of reddish, round to oval well defined scaly lesions with sharply demarcated borders. Sites: Elbows, knees, outer surface of extremities, scalp &low back in a symmetric pattern. Palms/ soles involved commonly.
Types
- Chronic plaque psoriasis: plaques with less scaling
- Annular psoriasis: ring-shaped or other patterns
- Guttate psoriasis: Common in children, good prognosis, following infections
- Pustular psoriasis: Crops of pustules based on redness
- Erythrodermic psoriasis: skin peels off from the whole body
- Psoriatic arthritis: with joint involvement
Psoriasis in children:
Lesions not as thick as in adults, less scaly, Diaper area in infants, flexural areas in children.
Psoriasis in HIV:
Acute onset, with severe flares and less chance of recovery
Complicated psoriasis
Erythrodermic psoriasis, Generalised pustular Psoriasis psoriatic arthritis
Treatment
General measures:
Counselling regarding the natural course of the disease, weight reduction in obese patients, avoidance of trauma or irritating agents, reduced intake of alcoholic beverages, reduced emotional stress, sunlight and sea bathing improve psoriasis.
Topical Therapy used are emollients: white soft paraffin & liquid paraffin, corticosteroids, coal tar ointment, dithranol ointment, Salicylic acid, urea. Effects of topical therapy evident in 2-3 weeks. There will be clearing of scale is usually observed first, followed by flattening of the treated plaques. Redness may resolve in 6-8 weeks.
Phototherapy is used for extensive and widespread disease, resistance to topical therapy. Irradiation with light which is effective for moderate to severe psoriasis, usually combined with one or more topical treatments like tar or anthralin. UVB phototherapy using narrowband spectrum is very usefull.
Systemic agents are indicated in cases which are resistant to both topical treatment and phototherapy, active psoriatic arthritis, physically, psychologically, socially or economically disabling disease. Drugs used are methotrexate, cyclosporine, retinoids. Newer biologicals are immunologically directed intervention at key steps in the pathogenesis of the disease.
The course of plaque psoriasis is unpredictable. Characterised by remissions and relapses often intractable to treatment. They can relapse in most patients, improves in warm weather.
Dr Gatha M Upadya
Professor & Head,
Dept of Dermatology,
KMC Hospital,
Attavar, Mangalore