Last reviewed by Editorial Team on August 13th, 2018.
What is Plaque Psoriasis?
Plaque psoriasis is also called as psoriasis vulgaris and is regarded as the most common type of psoriasis. This common type of psoriasis is marked by the development of thickened portion of the skin that may be small or large in size and is reddish and scaly in appearance and with well demarcated borders. It usually occurs in the lower back, elbows and knees but may also occur in any part of the body.
Plaque psoriasis is a form of psoriasis where the latter is described as a chronic and relapsing inflammatory disease of the skin. The disease is immune mediated where a flawed signal triggers the skin cells to reproduce rapidly. This results to build up as new skin cells are formed rapidly as compared to the normal process. Due to the rapid formation of new skin cells, the old skin cells are unable to shed off thereby causing the buildup on the surface of the skin leading to formation of patches characteristic of psoriasis.
Plaque psoriasis can affect many people regardless of racial group although high prevalence is found in the Western Europe and is seldom found in West Africa. It equally affects both men and women, but is found to be more prevalent in female children and adolescents. The first peak of onset is between the ages of 16 to 22 years while the second peak of onset is between the ages of 57 to 60 years.
Mortality related to plaque psoriasis itself is rather rare and may be associated with the therapy which can initiate skin cancer or which can aggravate the disease further that can prove to be fatal. The disease however can bring psychological distress on the part of the patient. The clinical presentation of the disease can bring in embarrassment due to the unappealing appearance of the patches. This can affect the quality of life of the patient.
Types of Plaque Psoriasis
Plaque psoriasis has several types which are classified according to the presentation of plaques and the location of its development.
The different types of Plaque psoriasis are the following:
Small plaque psoriasis
Small plaque psoriasis appears in multiple small skin patches with the size of about a few millimeters to a few centimeters in diameter. The plaques are characteristically thin or skin thin that it almost merges with the normal surrounding skin. It has a pinkish and fine scaly appearance and is common in people over the age of 40 years. This type of plaque psoriasis responds well to phototherapy treatment.
Large plaque psoriasis
Large plaque psoriasis occurs in people under the age of 40 years and is associated with a family history of psoriasis. The plaque is characterized by thick, reddish and silvery scales with well demarcated borders. This type of psoriasis responds poorly to treatment.
Lichenified plaque psoriasis
Lichenified plaque psoriasis is characterized by a very thick plaque that resulted from constant rubbing and scratching due to the itchiness of the skin patches.
Ostraceous psoriasis appears similar to the shell of an ostrich. This type of psoriasis is extremely thickly scaled and the areas of psoriasis are ring-like in presentation.
Rupioid psoriasis is a cone shaped or limpet-like type of plaque psoriasis. This form of plaque psoriasis is characterized by hyperkeratotic lesions.
Linear psoriasis is the type of plaque psoriasis that is arranged in linear along the body and often matches with fetal developmental lines.
Koebnerised psoriasis is the type of plaque psoriasis that often develops in the area of the skin previously injured or underwent surgical incision and experienced infection.
Photosensitive psoriasis is the type of plaque psoriasis that gets worse when exposed under the sun and usually occur in sun exposed areas of the body such as the face, neck, forearms and hands. This type of plaque psoriasis requires a strict sun protection along with the treatment of psoriasis. Exposure to the sun will result to flare-ups of plaques leading to clear sunburn-like lines. Patients with this type of plaque psoriasis are also found to have the typical plaque psoriasis that develops elsewhere in the body. Ultraviolet light is found to be beneficial in this form of psoriasis.
Plaque psoriasis is the most common form of psoriasis that usually involves the scalp, face, lower back, outside areas of the knees and elbows but may also occur elsewhere in the body. The onset of plaque psoriasis may be chronic or persistent. Plaque psoriasis is marked by the development of skin patches that may be large or small and may be localized or generalized. It is generally characterized by silvery scales that may merge together to involve massive areas of the skin and are distributed symmetrically.
The plaques are characterized as follows:
- The shape is circular to oval or may be irregular and with well demarcated borders
- The size of the plaques varies, ranging from a few millimeters to several centimeters in diameter
- The color of the plaques may be in rich red and often bluish in the legs
- The texture of the plaques are somewhat scaly and dry and with silvery white color
- The plaques may be large or may be in small size which may merge together to form larger plaques particularly in the areas of the legs and the sacral region
- The plaque may also be accompanied or encircled by a paler skin
- Plaque psoriasis in children have a slight difference wherein the skin patches formed are not as thick as those in adults and are often located in the flexural areas or in the nappy region of the child and scaling is noted to be less compared to adults
- Fissuring can occur in the plaques when it develops in the joints and in the palm of the hands and soles of the feet
The onset of plaque psoriasis is often associated with other symptoms aside from the development of the plaques. Such manifestations of plaque psoriasis may include the following:
- Pruritus or itchiness is one of the major symptoms of plaque psoriasis
- Pain in the affected area is also among the main symptoms
- Nails may have pitting and hyperkeratosis
- Warmth and tenderness may be present when psoriatic arthritis is involved
- Joint deformity may occur especially if plaque psoriasis occurs in the joint areas of the body
Several factors are considered in the incidence of plaque psoriasis and such may include the following:
- Genetic factor is the most implicated in the incidence of plaque psoriasis. The inheritance of the disease is believed to be passed on to offspring in an autosomal dominant pattern.
- Exposure to sunlight is considered a factor in a small number of cases of plaque psoriasis, despite the sunlight being beneficial to other patients of plaque psoriasis.
- Trauma to the skin such as infection, surgical wounds and inflammatory injury are all considered to contribute to the incidence of plaque psoriasis.
Plaque psoriasis requires a long-term treatment and the treatment plan is usually customized based on the needs of the patient including the age, gender and overall health condition of the patient.
The treatment for plaque psoriasis may include the following:
- Topical treatment is the first line of treatment and which may or may not have steroid. Topical treatment acts by slowing down the skin cell production and by reducing the inflammation.
- Phototherapy is intended for extensive and severe psoriasis. This method is effectively done through exposure of the affected skin under the ultraviolet light.
- Systemic medications are given for extensive and severe psoriasis and those that remains unresponsive to topical treatment. The treatment is given orally or may be injected or infused into the patient.