Psoriasis is a skin disorder that is non-contagious and is suspected to have autoimmune and hereditary etiology. This condition has several types of presentations; and one type of psoriasis may be present at a time. Throughout the lifetime of an individual with psoriasis, when one type would be clear, another form of the condition would present itself.
Clinically, psoriasis is described as a papulosquamous disease with variable morphology (shape and appearance), distribution of lesions, severity or intensity of the disease, and course or speed and evolution of the disease .
Papulosquamous diseases are characterized by scaling papules and plaques. Papules are raised lesions greater than 1 cm in diameter while plaques are lesions raised less than 1 cm in diameter.
There are a lot of factors that may trigger a psoriasis attack. Once triggered, the presentations of psoriasis may be classified into three main groups: pustular, non-pustular psoriasis and others with sub classifications.
Non pustular psoriasis has two sub classifications that include psoriasis vulgaris (plaque psoriasis) and psoriatic erythroderma (erythrodermic psoriasis).
Under pustular psoriasis, it has sub groups which are categorized as generalized and localized; and other specific types as well.
The other presentations that do not fit under pustular or non pustular classifications are grouped under the others category
Each type of psoriasis will be discussed below to provide quality information and develop a deeper understanding about psoriasis.
This group consists of the different types of psoriasis in which accompanying lesions do not contain pus (pustules) within.
Plaque psoriasis (psoriasis vulgaris)
Also called chronic stationary psoriasis, is the most common form of psoriasis affecting 80-90% of people with psoriasis.
Plaque psoriasis appears as raised, easily palpable areas of inflamed skin covered with silvery white scaly skin (plaques). The lesions are due to the thickened epidermis and increased vascular compartment (blood vessels and blood) and proliferation of cells from the immune system (neutrophils and lymphocytes).
The scales are caused by buildup of dead skin brought about by the abnormal production of skin cells associated with psoriasis.
These often itchy and painful lesions most often appear on the scalp, knees, elbow, and lower back and soles of the feet.
This involves the widespread inflammation and exfoliation of the skin that involves the whole body including the face, hands, feet, extremities, nails, and trunk.
Pain, inflammation, and severe itching are associated with this presentation. Hallmark signs of this condition are increased heart rate, ankle swelling (edema), and erratic temperature especially during extreme environmental temperatures.
Psoriatic erythroderma is usually the exacerbation of unstable plaque psoriasis, particularly following abrupt withdrawal of systemic treatment.
Although this type of psoriasis is uncommon; once it presents itself, medical help should be sought immediately. Hospitalization is needed as psoriatic erythroderma may lead to severe illness due to protein and fluid loss.
This imbalance in the body’s chemistry would result to usually fatal conditions like pneumonia, infection, and congestive heart failure.
Pustular psoriasis appears as raised bumps filled with non infectious fluid (pustules). The skin under the pustule is red and tender. Lesions of pustular psoriasis may be localized or generalized. The following are the types of pustular psoriasis:
Generalized pustular psoriasis (GPP)
An extremely rare form of psoriasis, generalized pustular psoriasis lesions cover the entire body with pus-filled pustules rather than plaques. It can present itself at any age but is rarer in children. It can appear with or without previous psoriasis experience and can recur in periodic episodes.
It differs from the localized form of psoriasis is that patients with GPP are often febrile and systematically ill. The prominent sign of GPP is the sheeted, pin-sized, sterile, sub corneal pustules. These pustules often occur either at edges of expanding, intensely inflammatory plaques or within erythrodermic skin.
Localized Pustular Psoriasis
These are types of psoriasis in which the distribution of pustular lesions are on specific sites of the body.
Annular pustular psoriasis
A rare variant of pustular psoriasis, having an annular or circinate lesion morphology that may appear at the onset of pustular psoriasis, with a tendency to spread from enlarged rings. It is commonly localized but a generalized variant may also occur.
Pustulosis Palmaris et plantaris
Also known as pustulosis of palms and soles, palmoplantar pustulosis, pustular psoriasis of the extremities, and pustular psoriasis of the Barber type, this condition is a chronic recurrent pustular dermatosis localized on the palm and soles.
Tissue examination characteristically shows presence of neutrophils (immune system cells) within the intradermal vesicles.
Impetigo herpetiformis is a form of severe pustular psoriasis occurring during pregnancy. This may occur during any trimester. This is the only well known pustular psoriasis treated with steroids.
Other Types of Psoriasis
This group consists of types of psoriasis that do not belong to neither pustular nor non-pustular categories.
Also called flexural psoriasis, this type of psoriasis appears as smooth inflamed patches of skin. It occurs in skin folds, particularly around the genitals (between thigh and groin), the armpits, under an overweight abdomen (panniculus), and under the breast (inframammary fold). Inverse psoriasis is aggravated by friction and sweat. It may also appear on the lips, nose, armpit, navel, and any other area with folds and contour.
The lesions of inverse psoriasis are red, smooth, and shiny in appearance. This differentiates it from that of plaque psoriasis. This type of psoriasis is also prone to fungal infections due to the moist environment of the areas involved.
Also known as “eruptive psoriasis” is a type of psoriasis that presents as small (.5-1.5cm in diameter), salmon-pink, lesions over the back and proximal extremities, but may also occur on any area of the body. It is classically triggered by a bacterial infection, usually a respiratory tract infection.
After the infection has cleared, red spots are noticed which are itchy. When scratched or picked, the top layer of dry skin is removed, leaving red, dry, red skin beneath with white, dry areas marking where flakes of dry skin stop and start.
In the weeks that follow, the spots may grow to as much as an inch in diameter. Some of the larger areas may form a pale area in the center which is slightly yellow.
This nail disease is common among persons suffering from psoriasis; especially those with psoriatic arthritis. Nail psoriasis affects the fingernails more than the toenails. Nail psoriasis is characterized by various nail changes such as changes in nail shape, discoloration, presence of pits or holes, lines across the nails, thickening of the skin under the nail, or in severe cases detachment of the nail from the nail bed.
This involves both joint and soft tissue inflammation. Psoriatic arthritis can occur on any joint, but is most common in the joints of the fingers and toes. The hips, knees, and spine may also be affected.Signs and symptoms of psoriatic arthritis include:
- pain, swelling, and stiffness of one or more joints
- sausage-like swelling of the roes and fingers (dactylitis)
- painful tendons especially around the ankles
- nail changes
Along with the signs and symptoms of inflammation, there is extreme exhaustion that does not go away with adequate rest. The exhaustion may last for days or weeks without relief. Psoriatic arthritis may remain mild or may progress to a more destructive joint disease.
Each presentation of each type of psoriasis would require a different approach in terms of treatment and management. It is highly recommended to identify and understand what presentation is present and manage it promptly.