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Psoriasis: Clinical Presentation, Diagnosis And Treatment
A General Overview
This is a chronic inflammatory condition of the skin in which the etiology is largely unknown. It is transmitted as an autosomal dominant trait with irregular penetrace and therefore, it is found more commonly among family members of cases. Around 30% of all cases give a positive family history. All age groups may be affected, although it is rare in infancy and old age. There is no evidence of any infection in these lesions. Both sexes are affected equally.
The lesions appear as erythematous well demarcated patches with loosely adherent silvery scales, when the scales are removed, hyperemia or bleeding points become visible “Auspitz sign". The lesions vary in size and shape. Coalescence of lesions results in the formation of plaques of various geographical patterns. Though all regions of the body can be affected, the common sites of predilection are extensor aspects of the knees and elbows, the scalp, and the sacral region. The disease undergoes spontaneous remission and relapse at variable intervals. Though not a fatal disease, in some it may become very extensive and change over to exfoliative dermatitis or it may show involvement of joints.
Involvement of the nails results in the formation of pin-point sized pits on the surface of the nail plates. The nail plate may get separated from the nail bed by subungual hyperkeratotic material or the nail may become thick and discolored. Irregular furrows may develop on the nail plate. Depending on the morphology or the lesions, various descriptive terms are employed, e.g, “Psoriasis guttata”. When the lesions are of the size of drops and “psoriasis follicularis” when the lesions are found in relation to the pilosebaceous follicles. Psoriasis figurative, psoriasis annulata, psoriasis gyrate and psoriasis discoidae are all terms which describe the morphology of the lesions. Flexoral psoriasis is a definite regional type confined to the flexural aspects.
Several other variant forms of psoriasis exist in addition to the classical forms. These are ‘seborrheic dermatitis like’ psoriasis, lichen planus-like psoriasis, psoriatic erythrodermia and pustular psoriasis. These are less frequent.
Diagnosis And Treatment
Psoriasis has to be differentiated from conditions such as seborrheic dermatitis, secondary and tertiary syphilis, pityriasis rosea, tinea circinata, lichen planus etc. The course of psoriasis is unpredictable. The initial attack may heal completely but it is impossible to predict how long the freedom will last and when the next attack would set in. In cases with incomplete remission, the disease-free interval is likely to be shorter than in cases with complete remission.
Local application: An ointment containing salicylic acid 3%, ammoniated mercury 1%, liquor picis carbonis 6% and icthyol 12% in Vaseline base is massaged into the lesion. In many cases, this leads to regression of the lesions within a few weeks. An alternative is an ointment containing crude coal tar (4 to 10%) or dithranol.
Systemic therapy: Psoriasis associated with acute arthritis or which has developed exfoliative dermatitis, responds to systemic corticosteroids. Recently, treatment regimes including oral psoralens followed by ultraviolet light exposure have been advocated (PUVA therapy). In lesions resistant to local therapy, intralesional injections of corticosteroids and occlusive dressing with corticosteroid ointment have been tried with success.
Antimetabolites like methotrexate and other cytotoxic drugs have been employed to inhibit the rapid mitoses of the epidermal cells. Due to their potential toxicity, they should be given only in resistant and extensive cases.
© 2014 Funom Theophilus Makama