Doctors diagnose psoriasis based on how much of the body it affects. Mild psoriasis affects less than 3% of the body, while moderate psoriasis affects 3–10% of the body. Severe psoriasis affects more than 10% of the body.
Psoriasis is not necessarily easy to deal with even when it is mild. Psoriasis of any type or severity can be uncomfortable and embarrassing. Fortunately, there are many treatments available that can help.
In this article, we take a look at different types of psoriasis, and in particular how they can affect people in their mild forms.
Psoriasis is a skin condition that causes skin cells to form too quickly. Because new skin cells grow faster than the body sheds existing skin cells, thick, scaly patches of skin form.
There are several types of psoriasis. Most types of psoriasis tend to be mild to moderate. However, some types of psoriasis are more likely to be severe.
Types of the condition include:
- plaque psoriasis
- psoriasis of the scalp
- guttate psoriasis
- inverse psoriasis
- pustular psoriasis
- erythrodermic psoriasis
People with psoriasis may develop one type of psoriasis and then develop another type at a later point in time.
While symptoms vary with the type of psoriasis a person has, most people with psoriasis will experience some combination of the following symptoms:
- itchy skin
- burning, sore, or painful areas on the skin
- patches of thick skin with silvery scales
- small scaly spots
- swollen or stiff joints
Psoriasis symptoms tend to be cyclical. This means that they will often become more intense during what are called flares and lessen at other times.
During flares, symptoms may be more severe even in cases of mild psoriasis. At other times, symptoms may be minimal.
Plaque psoriasis, also known as psoriasis vulgaris, is the most common form of psoriasis. It is marked by areas of plaque buildup on the skin.
Plaque is the thickened areas of skin that often have a white or silvery, scaled appearance. They tend to appear most on elbows, knees, and lower back but may form anywhere on the body.
Plaque psoriasis tends to be mild to moderate. Mild plaque psoriasis covers less than 3 percent of the body, and moderate plaque psoriasis covers less than 10 percent of the body.
Symptoms of plaque psoriasis vary from person to person. These symptoms can include the following:
- areas of dry, red skin lesions covered with silvery scales
- plaques that itch or burn
- problems that affect the nails
Areas of plaque may appear anywhere on the body but are most common on the knees and elbows.
Treatment of mild or moderate plaque psoriasis varies and often requires trial and error before determining the best treatment combination for that person.
Treatment options include the following:
- exposing the skin to ultraviolet (UV) light
- creams and ointments applied to affected areas to slow down skin growth
Drugs that affect the whole body are rarely used for mild psoriasis. However, these drugs may be used if other treatments fail.
When psoriasis appears on the scalp, it is known as scalp psoriasis. It can appear on the forehead, or back of the head and extend down the neck or behind the ears.
Scalp psoriasis usually has the same symptoms as plaque psoriasis. In scalp psoriasis, the plaques appear on the scalp and under the hair.
A person with scalp psoriasis can have psoriasis on other parts of their body at the same time.
Other symptoms of scalp psoriasis include:
- red patches of thick skin on the scalp
- silvery dandruff-like flakes on the scalp
- itching and bleeding scalp
- a dry scalp
- temporary hair loss during flares
Treatment for scalp psoriasis often involves more than one method at a time. As with plaque psoriasis, it may take some time to find the best approach for the individual.
Treatment options for scalp psoriasis include:
- medicated shampoos and ointments
- UV light therapy
- scalp therapy
In more severe cases, drugs that affect the whole body may be added to a treatment plan.
Guttate psoriasis is characterized by red dots and spots spread throughout the skin. The dots and spots are not as thick as plaques in plaque psoriasis.
This type of psoriasis often starts in childhood or young adulthood and appears after an infection.
Most often, guttate psoriasis is mild psoriasis. In some cases, however, it may cause moderate to severe symptoms. Symptoms may include the following:
- small, red spots on the skin
- potentially hundreds of red dots on skin
- a rash that can appear anywhere but mostly on the trunk
- sudden onset of a rash after illness or infection
Most doctors consider topical treatments very effective for guttate psoriasis. However, people with guttate psoriasis may find applying the cream on so many individual spots very tiring, so topical treatments may be used more when the rash is confined to a smaller area.
Other treatment options include light therapy. Doctors rarely use drugs affecting the whole body for guttate psoriasis.
Inverse psoriasis appears as red marks that are most often found in the folds of the skin, such as in the armpits and groin.
People with inverse psoriasis often have other forms of psoriasis elsewhere on their body.
Areas of the body that are most likely to be affected by inverse psoriasis include:
- under the breasts
- behind the knee
Areas affected by inverse psoriasis rarely have scaly plaques that are common with other forms of psoriasis.
The areas of the body that are most often affected by inverse psoriasis tend to be quite sensitive and have thinner skin than other areas. This can make treating this type of psoriasis more difficult.
Steroid creams and ointments are effective, but the risk of side effects is higher due to the thinness of the skin.
This type of psoriasis is marked by white blisters that contain pus. This pus is not infectious and is made of white blood cells.
The blisters that are caused by pustular psoriasis can be limited to one area of the body or appear more generally across the whole body.
Before the blisters appear, the skin tends to redden. Once the blisters have gone away, the skin may become scaly.
A specific kind of pustular psoriasis called palmoplantar pustulosis causes blisters to form on the palms and soles of the feet. These blisters form in a studded pattern. Over time, the blisters turn brown and become crusty.
Some forms of pustular psoriasis can be difficult to treat. Doctors will often switch between oral medications and light therapy, to reduce the risk of side effects.
Acitretin and methotrexate are two drugs that can treat the condition quickly and clear up the affected areas of skin.
Pustular psoriasis that only affects one area of the body may also be treated with medication applied to the skin.
While most forms of psoriasis tend to be mild or moderate, erythrodermic psoriasis is severe and can be a life-threatening medical emergency.
This type of inflammatory psoriasis covers most of the body in a red, peeling, extremely painful rash that looks as if it has been caused by a burn.
Unlike symptoms of the types of psoriasis that are usually mild, symptoms of erythrodermic psoriasis tend to be very serious. They may include a combination of the following:
- widespread area of inflamed, red skin
- skin that peels off in sheets
- skin that looks as if it has been burned
- severe itching, pain, or burning
- faster heart rate
- fever or lower body temperature
- swelling in feet or ankles
People with erythrodermic psoriasis are often hospitalized. Unlike in cases of mild or moderate psoriasis, topical creams are not the first line of treatment. Instead, most people with erythrodermic psoriasis need drugs that affect the whole body.
Most types of psoriasis tend to be mild to moderate. This exception is erythrodermic psoriasis, which can be a life threatening medical emergency.
Psoriasis varies in its appearance and symptoms, but most treatment approaches are very similar. Most people with mild psoriasis can manage their symptoms using topical treatments, according to treatment guidelines published in 2019.
If a person has moderate to severe symptoms, however, a doctor may prescribe one of a relatively new class of drugs called biologics. These can help treat the underlying cause of skin changes and may reduce the number of flares and severity of symptoms.
People who suspect that they have psoriasis should consult their doctor before beginning treatment. People with symptoms of erythrodermic psoriasis should seek immediate medical attention.