Common clinical types of psoriasis are guttate psoriasis, common plaque psoriasis, inverse or flexural psoriasis, pustular psoriasis and erythrodermic psoriasis.
Guttate psoriasis
Guttate Psoriasis is a special variant which primarily occurs in children and young people following a streptococcal throat infection. Drop-like, scaly patches appear on the entire body. In many cases, the condition disappears by itself after a few weeks or months. This type of psoriasis responds very well to systemic antibiotics.
Common Plaque Psoriasis
Plaque psoriasis is the commonest type of psoriasis, also known as psoriasis vulgaris, occurring in about 80% of psoriasis patients. Common plaque psoriasis usually begins as small, erythematous, scaly papules that gradually enlarge to form well demarcated, raised, erythematous plaque with a scaly surface.
The scales in psoriasis are typically silvery white, dry, brittle and arranged in a lamellated fashion. This silvery white color is due to refraction of light through the air trapped in between the scales. The upper scales fall off in large quantities, while the lower layers of scales are firmly fixed. Scraping the scales reveals minute bleeding points (auspitz sign).
Inverse or Flexural Psoriasis
This type of psoriasis occurs in skin folds (flexures). Red, itchy plaques appear in the armpits, under the breasts, on the stomach, in the groin or on the buttocks. The plaques are often infected by the yeast-like fungus candida albicans. Scales are usually absent in inverse psoriasis.
Psoriasis Nails
Psoriasis of the nail often manifests itself as small indentures in the nails. These are known as nail pits. Nail pits, though, is not a feature of psoriasis alone; many other skin conditions like alopecia areata can be associated with nail pits.
When the nail involvement is severe, the nail thickens and crumbles away. Nail involvement is most common when psoriatic joint (psoriatic arthritis) involvement is present.
Psoriasis of the Scalp
Psoriasis of the scalp can be difficult to distinguish from a severe case of dandruff or seborrheic dermatitis, and sometimes the two occur simultaneously. Thick scaly plaques localized to certain areas are typical of psoriasis scalp.
Pustular Psoriasis
Pustular psoriasis is a rare variant where the inflammation is so severe that, in addition to the usual lesions, blisters or pustules containing fluid appear on the skin. This can be localized to the palms and soles or generalized, spreading all over the body
Erythrodermic Psoriasis
Erythrodermic psoriasis is the most severe form of psoriasis, which resembles a bad case of severe sun burn with redness, scaling and swelling of the skin all over the body.
Psoriatic Arthritis
In around 10 to 30% psoriasis patients, a debilitating joint disease, known as Psoriatic Arthritis may develop. It causes inflammation in and around the joints and affects an estimated 28 million psoriasis patients. People with psoriatic arthritis experience progressive joint pain and swelling, which is often coupled with scaly, red skin lesions on other areas of the body.
Clinical Types of Psoriasis According to Activity
- Acute Eruptive Psoriasis:This is the guttate variety which suddenly appears all over the body
- Chronic Progressive Psoriasis: The common plaque psoriasis, also known as psoriasis vulgaris. This gradually progress in size and number.
- Chronic Stationary Psoriasis:When the psoriasis lesions remain stationary without increasing in size and with a dull red colour and minimal scaling, this is a stationary stage. This stage usually precedes the regressive stage.
- Chronic Regressive Psoriasis:With or (sometimes) without treatment, psoriasis lesions gradually become thin, scaling reduces, the red color changes from dull red to violaceous and gradually fade. In those who have used steroids or ultraviolet radiation, a hypo pigmented (whitish) ring known as Woronoff’s ring may be seen surrounding the lesion.
Choice of treatment differs for each of these types of psoriasis.
Next: Guttate Psoriasis, the Least Severe Psoriasis.
Reference
Psoriasis, in Rook’s Textbook of Dermatology, 7th Edition, 2004
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