Different manifestations of psoriasis are equally common among both sexes, although a recent study found that on average men have heavier forms of psoriasis than women. Five types of psoriasis have been described: plaque (also known as ordinary psoriasis); droplet-shaped, or eruptive, which is characterized by droplet-shaped spots covered with branched scales; inverse, also called interrigenous, or flexural, or psoriasis of bending surfaces, which is usually located in the folds of the skin; psoriasis, which can take the form of both palm-saline psoriasis and generalized psoriasis (a rare and serious form); and psoriatic erythrodermia, which is a rare and very serious complication of psoriasis.
Picture 1: Clinical manifestations of psoriasis. The Lancet Typical erythematous plaques with silver scales (A) may be scattered (B, numeral psoriasis), cover large areas of the skin (C, geographical or garland psoriasis) or affect the entire body surface (D, psoriatic erythroderma). Affection of the scalp may be accompanied by non-rubic baldness (E). Psoriatic arthritis affects up to 30% of all patients (P, interphalangeal joint of the thumb). Nail changes are common and range from point pressure and yellow or brown dyschromia (G), to complete dystrophy (H). Foci of inverse psoriasis occur in areas of intertrigo and are usually devoid of scales (I). Pustular psoriasis may be in the generalized form (J, K), or local (L, palm-plate type and M, persistent pustular acrodermatitis Allopo). In children, droplet psoriasis may occur after an upper respiratory streptococcal infection (N) and on any part of the body (O, P, Q).
Chronic plaque (or common) psoriasis is the most common form of disease, and accounts for about 90% of cases. Typical foci are monomorphic, sharply delineated erythematous plaques covered with silver scales (image 1A). Plaques can be multiple (image 1B), they can spread over large areas (image 1C), and they can also look like erythrodermia covering the entire body surface (image 1D).
Erythroderma is a potentially life-threatening disease, and any form of psoriasis can become erythrodermic. Search strategy and selection criteria. We reviewed PubMed using the terms “psoriasis”, “epidemiology”, “pathogenesis”, “genetics”, “loci of predisposition to psoriasis”, “therapy”, “methodological guidelines”, and “related diseases”. Our search included articles published in English, French and German between 1974 and May 13, 2015. We found additional information from this list of fundamental reviews. Psoriasis can affect any part of the skin; however, typical localizations (favorite places) include forearm and shin extensor surfaces, parotid area, scalp, perianal and behind-the-ear areas. Affection of the scalp hair part develops in 75-90% of patients with psoriasis, and non-rubic alopecia is also not uncommon (image E).
Psoriatic lesion of the nails (psoriasis of the nails of the hands or feet) is found in about 50% of patients, and of them up to 80-90% of patients stay with it for life. Moreover, up to 90% of patients with psoriatic arthritis (image 1F) showed nail involvement. Mild psoriatic changes to the nails include pinpoint dystrophy of the nail and dyschromia in the form of yellow or brown spots below it (image 1G).
The nail plates thicken and crumble, the final stage of psoriasis of the nails is realized in complete dystrophy of the nails, which exhausts the patients. Inverse psoriasis is a localized variant of psoriasis, which occurs on bending surfaces and in folds (image 1I) and usually has no scales on the surface of the centers due to friction and humidity in these places. Sebopsoriasis occurs when psoriasis and seborrheic dermatitis occur simultaneously, and it usually develops on the face, scalp and chest skin.