Types of psoriasis: symptoms, causes, treatment

You’ve probably heard it said that the skin is the largest organ in the body. This multi-layered organ plays several important roles, from regulating your body temperature to protecting your bones and muscles. At times, skin can experience irritation, like rashes, from outside factors — but other times, the state of the body itself can cause skin problems. For example, inflammation due to immune system activity plays a big part in various types of psoriasis (Greb, 2016). 

Read on to learn more about the various types of psoriasis, including symptoms of psoriasis, causes, and treatments. 

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Psoriasis is a chronic inflammatory condition that typically causes raised red patches covered in silvery scales on the skin. On black skin, the lesions can appear as purple patches with gray scales or as a dark brown color (Nair, 2021). Simply put, experts believe that psoriasis is caused by an overactive immune system which leads to inflammation and overproduction of skin cells (Nair, 2021; Greb, 2016).

Psoriasis can affect other areas of the body, such as the joints, and may cause abnormalities of other bodily systems (Badri, 2021). Some people also experience nail psoriasis (Merola, 2018).

Psoriasis affects about 0.5–11% of adults, and it can significantly impact a person’s quality of life, including poor self-esteem, anxiety, and sexual dysfunction (Michalek, 2017; Kim, 2021).

While genetics play a key role in psoriasis, certain things can trigger it, such as infections, stress, alcohol use, smoking, and obesity (Nair, 2021). According to estimates, one-third of those with psoriasis have a first-degree relative with the condition (Weigle, 2013).

There’s no cure for psoriasis. Typically, the condition occurs in flare-ups and periods of remission. Several effective psoriasis treatments are available, from topical steroids to systemic drugs and phototherapy (Greb, 2016). Ultimately, how a healthcare provider treats psoriasis depends on how severe it is and what type of psoriasis a patient has (Armstrong, 2020).

Here is an overview of the different types of psoriasis: 

Plaque psoriasis is the most common type of psoriasis and can be difficult to treat as people react to treatments in different ways. In addition to causing skin symptoms, it can impact people’s quality of life (Sbidian, 2017). 

Plaque psoriasis symptoms

Plaque psoriasis symptoms typically include large, oval, or circular plaques that often occur on the scalp, trunk, and skin over the joints, along with scaling. It’s often itchy, and in some cases, it can cause disfigurement. It's common for people with plaque psoriasis to also have psoriatic arthritis, a chronic inflammation of the joints that resembles rheumatoid arthritis (Badri, 2021). 

Like other types of psoriasis, plaque psoriasis is often linked to other conditions, such as cardiovascular disease. It’s not entirely clear why other diseases are linked to psoriasis, but experts think that chronic inflammation, lifestyle factors, and the adverse effects of therapies might play a role (Armstrong, 2020).

Plaque psoriasis causes

Simply put, plaque psoriasis happens due to an interplay of autoimmune activity, inflammation, and rapid build-up of skin cells. Normal skin cells grow and shed in a month, but with psoriasis, these cells grow and die faster, and instead of shedding, they pile up on the surface of the skin, resulting in scaly areas called plaques (Sbidian, 2017). 

Plaque psoriasis can affect a person’s skin, joints, or both. People with a genetic predisposition are more likely to have plaque psoriasis, but other factors may trigger it, such as obesity, stress, alcohol, and smoking (Albaghdadi, 2017).

Some prescription drugs, including beta-blockers, lithium, and antimalarial medications, can make psoriasis worse. Scratching can trigger or worsen plaque psoriasis (Balak, 2017; Badri, 2021). 

Plaque psoriasis treatment

Sunlight can help people with plaque psoriasis, and phototherapy is one treatment option. Topical agents that may improve psoriasis symptoms include coal tar, corticosteroids, and vitamin D. In general, topical therapy and phototherapy are best for mild or moderate plaque psoriasis, while more severe cases might respond better to systemic drugs (Badri, 2021).

Two common drugs for plaque psoriasis are steroids and biologics. Steroids are a type of drug that suppresses the immune system (Hodgens, 2021). Biologic drugs also suppress the immune system, but they work by targeting specific parts of the immune system that may fuel inflammation and cause psoriasis (Sapkota, 2021). Studies have shown biologic drugs work better than placebo in treating moderate to severe psoriasis (Albaghdadi, 2017).

A less common type of psoriasis is pustular psoriasis, characterized by yellow, pimple-like pustules on red skin areas (Shah, 2021).

Pustular psoriasis symptoms

Pustular psoriasis lesions can contain pus, and unlike plaque psoriasis, pustular psoriasis often involves pain upon being touched (Saleh, 2021; Shah, 2021). 

Generalized pustular psoriasis (GPP), a rare subtype of pustular psoriasis, is also characterized by painful and pus-filled skin lesions affecting large areas of the body. Acute episodes of GPP can be accompanied by fever, chills, and malaise, and sepsis is a serious complication. Even though it’s rare, GPP can be life-threatening and requires emergency medical care. It typically begins with red, and tender skin, followed by widespread pus-filled blisters within hours (Hoegler, 2018).

Pustular psoriasis causes

Most cases of pustular psoriasis have no known cause. However, some risk factors might play a role in the development of the condition (Shah, 2021): 

• Steroid withdrawal 

• Skin infections

• Electrolyte imbalance (hypocalcemia)

• Medication 

• Pregnancy

The causes of generalized pustular psoriasis (GPP) are not fully understood. Besides genes, viral or bacterial infections, drugs, stress, and pregnancy might be triggering risk factors. It’s also often associated with metabolic syndrome and polyarthritis (Mirza, 2021).

Pustular psoriasis treatment

Pustular psoriasis is one of the types of psoriasis that can be challenging to treat; doctors may use more than one treatment, such as a combination of topical and systemic drugs, to improve people’s symptoms (Benjegerdes, 2016). Topical retinoids and immunosuppressive drugs can improve pustular psoriasis symptoms; biologic drugs have also been shown to improve pustular psoriasis symptoms (Wang, 2020).

In both pustular psoriasis and GPP, healthcare providers may treat the underlying condition if there is one (Shah, 2021). 

Guttate psoriasis is a type of psoriasis that can be triggered by an infection with streptococcal (strep) bacteria—the bacteria that cause strep throat. It can happen in adults, but it characteristically occurs in children and adolescents (Hall, 2019; Chalmers, 2019). 

Guttate psoriasis symptoms, causes, and treatment

Guttate psoriasis typically includes well-defined, scaly, red plaques, but it can also include pustules (pimple-like bumps). Some people with guttate psoriasis develop chronic plaque psoriasis (Saleh, 2021). 

The origin of guttate psoriasis is not well understood. Guttate psoriasis can surface 1-3 weeks after a strep infection (Saleh, 2021). People who already have plaque psoriasis can also experience guttate psoriasis flares after a strep infection (Hall, 2019).

As with other types of psoriasis, guttate psoriasis is usually treated with topical or systemic medications, depending on the severity. Biologic drugs can also help resolve guttate psoriasis plaques (Saleh, 2021; Hall, 2019).

Intertriginous psoriasis is characterized by lesions in a person’s skin folds, such as the armpits or groin (Merola, 2018). It’s also called flexural psoriasis or inverse psoriasis.

Intertriginous psoriasis symptoms, causes, and treatment

Intertriginous psoriasis involves skin lesions that are typically thinner than plaque psoriasis, usually with minimal scaling. Some researchers consider intertriginous psoriasis to be a subtype of plaque psoriasis. It is also linked with bacterial and fungal infections (Omland, 2015). 

There are several types of treatment for intertriginous psoriasis, including topical medications, phototherapy, steroids, and biologic drugs (Merola, 2018).

Psoriatic arthritis (PsA) is a type of chronic inflammatory arthritis that’s associated with psoriasis. While it involves psoriasis symptoms, it also shares characteristics with the autoimmune disease rheumatoid arthritis (Tiwari, 2021). According to estimates one in four people with psoriasis also has psoriatic arthritis (Alinaghi, 2019).

Psoriatic arthritis symptoms and causes

In addition to psoriatic skin lesions, psoriatic arthritis can cause joint pain, joint damage, stiffness, and nail lesions. It can also lead to inflammation in the fingers, toes, and tendons (Gottlieb, 2020). Psoriatic arthritis can affect other organ systems; for example, it’s associated with inflammatory bowel disease. It’s also linked to a higher risk of death from cardiovascular disease (Tiwari, 2021; Veale, 2018).

Psoriatic arthritis often stems from genetic factors. Many people with psoriatic arthritis have a relative with the disease (Tiwari, 2021). Environmental factors thought to trigger PsA include infection with the streptococcal bacteria and recent antibiotic exposure.

Psoriatic arthritis treatment

Those with mild arthritis often benefit from nonsteroidal anti-inflammatory drugs (NSAID), like ibuprofen. Biologic drugs—drugs that can modify the immune response—are recommended as a treatment for severe psoriatic arthritis but not everyone responds well to those medications (Raychaudhuri, 2017). 

Because it involves the joints, psoriatic arthritis may also require non-pharmacological treatments like physical therapy, occupational therapy, and exercise therapy (Tiwari, 2021).

If you have psoriasis symptoms, it’s important to see a healthcare provider as soon as you can for proper diagnosis and a treatment plan. 

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Current version

September 17, 2021

Written by

Ashley Abramson

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.