Histopathological Study of Psoriasis and Its Grading According to Trozak Scoring System

Abstract

Psoriasis (Greek. Psora, the itch) [1] is a chronic, relapsing papulosquamous disorder of undefined etiology, characterized by localized or generalized, mostly symmetrical, sharply demarcated plaques and papules, usually covered with white or silver scales [2] on the scalp, elbows, knees, lumbosacral area and in the body folds. Prevalence of psoriasis in countries vary between 0.09% [3] and 11.4%. [4] Psoriasis can occur at any age, and is most common in the age group 50-69. [5] It is considered equally prevalent in both sexes. [2,6] A seasonal variation of the disease, with a higher frequency of flares in winter and spring, has been seen. [7] The prevalence of Psoriasis varies among different ethnic groups and geographical locations, more common in colder northern zone compared to tropical zone.Clinical Presentations: Psoriasis affects skin and nails, along with associated arthritis and systemic diseases. The most frequently reported symptoms are scaling of the skin(92%), itching, erythema, fatigue, swelling, burning and bleeding. [8] Scale is characteristically silvery white and can vary in thickness. Removal of scale may reveal tiny bleeding points (Auspitz sign). The common clinical types of Psoriasis are summarised in the International Psoriasis Council classification and consist of plaque psoriasis, guttate psoriasis, pustular psoriasis, erythrodermic psoriasis, eczematous psoriasis, and photosensitive psoriasis. [9] Plaque type Psoriasis, also known as Psoriasis vulgaris, is the commonest form representing 70-80% of psoriatic patients. [10] Histology also varies among the different clinical variants. An identification of two subtypes of Psoriasis based on the "age of disease onset" has been described by Henseler and Christophers; Type I or Early Onset Psoriasis, presents at ≤ 40 years of age and Type II or Late Onset Psoriasis, developing after the age of 40. Multiple studies have shown that these two subtypes are clinically, genetically and immunologically heterogeneous. Early onset psoriasis, in contrast to Late onset psoriasis, is probably hereditary and shows HLA-Cw6 positivity and parental history with an irregular course, stronger tendency to become generalized, [7] more nail involvement and greater psychosocial impact. [11] Differential diagnoses of Psoriasis include Allergic contact dermatitis, Bowen