Generalized pustular psoriasis is a very rare and extreme form of psoriasis. It’s characterized by reoccurring flare-ups that cause pus-filled bumps and red skin over a large part of your body.

Generalized pustular psoriasis (GPP), also known as von Zumbusch psoriasis, can lead to life threatening complications and usually requires hospitalization.

Traditional psoriasis is called plaque psoriasis or psoriasis vulgaris. It usually causes flaky patches of skin in small parts of your body like your elbows or scalp.

Researchers originally thought that GPP was a subtype of plaque psoriasis, but it’s now thought to develop through a different pathway and is usually considered a separate condition.

It’s not clear how common GPP is in the United States. Researchers have estimated that it occurs in 1.76 and 7.46 people per million in France and Japan, respectively.

Keep reading to learn more about GPP, including what causes it, typical symptoms, and how it’s treated.

According to the American Academy of Dermatology Association, GPP starts with dry, red, and tender skin. Within hours, reddish and scaly pus-filled bumps appear over much of your body.

It typically also develops with other symptoms like:

Symptoms usually develop in flare-ups that last for 2 to 5 weeks. About 80% of people continue to have some degree of symptoms between flare-ups.

Symptoms of plaque psoriasis

According to the National Psoriasis Foundation, a little over half of people with GPP also have plaque psoriasis. Plaque psoriasis can cause dry, itchy patches of skin that usually develop on your:

  • elbows
  • knees
  • lower back
  • scalp

GPP seems to be caused by a combination of genetic factors and environmental triggers. It’s considered an autoinflammatory disease. Autoinflammatory diseases occur when your immune cells attack your tissues and cause intense inflammation.

GPP and gene mutations

Several gene mutations have been identified as contributing to the development of GPP.

Mutations in the IL36RN gene have been identified in people with GPP. IL36RN provides your body with the instructions to make a protein called interleukin-36 receptor antagonist. This protein helps regulate your body’s inflammation response.

Other mutations in the following genes have been identified as potentially contributing to the development of GPP:

  • CARD14, primarily in people with GPP and plaque psoriasis
  • AP1S3, primarily in people of European ethnicity
  • MPO

GPP and triggers

People who are genetically susceptible to developing GPP may experience flare-ups when exposed to certain triggers. Factors that have been identified as triggers include:

When it occurs during pregnancy, GPP is known as impetigo herpetiformis or pustular psoriasis of pregnancy.

GPP risk factors

Risk factors for GPP include:

GPP can cause life threatening complications, such as heart or lung failure. Older adults seem to be at the highest risk of serious complications. The mortality rate has been reported as 2% to 16%.

Other potential complications include:

Pregnant people are at risk of:

GPP is thought to be very rare, but it’s not exactly clear how many people develop it. Estimates from surveys and hospital data include:

CountryEstimated cases per 1 million people
South Korea88 to 124

People with GPP often need hospital treatment to manage complications like dehydration and poor body temperature regulation.

Many different medications are under investigation for treating GPP and some are used off-label. Off-label means a medication is used to treat a condition other than the conditions it’s been approved to treat.

SPEVIGO is the first medication approved by the Food and Drug Administration (FDA) specifically for GPP.


SPEVIGO (spesolimab) became the first FDA-approved medication to treat GPP in September 2022. In clinical trials, nearly half of people who received SPEVIGO had no signs of pus-filled bumps a week later.

SPEVIGO is administered through an IV. It works by blocking the activation of interleukin-36 receptors, which are involved in the development of GPP.


Biologics are medications that block the immune reaction in your body that causes psoriasis. Many different biologic drugs are being researched. Researchers are still trying to figure out which drugs are effective and what the side effects might be.

Another type of interleukin-36 inhibitor called imsidolimab is currently in phase 3 clinical trials and may be FDA approved if it’s found to be safe and effective. Previous clinical trials found promising results.

Other biologic drugs under investigation include:

  • TNF inhibitors: infliximab, adalimumab, and etanercept
  • IL-17 inhibitors: brodalumab, ixekizumab, and secukinumab
  • IL-23 inhibitor: guselkumab
  • IL-23 and IL-12 inhibitor: ustekinumab
  • IL-1 inhibitors: canakinumab, gevokizumab, and anakinra

Nonbiologic drugs

The most common nonbiologic drugs for treating GPP are:

DrugMechanism of action
RetinoidsIt may suppress the production of inflammatory molecules and normalize the division of skin cells.
CyclosporineIt blocks the production of inflammatory molecules.
MethotrexateIt might cause cells that make up your outer layer of skin to self-destruct.

Other treatments

Other treatments for GPP include:

  • topical treatments to soothe skin
  • fluids and electrolytes administered through an IV
  • light therapy
  • antibiotics to treat infections
  • treatment for specific complications like lung failure

GPP flare-ups can be life threatening if not treated promptly. Over half of cases require hospitalization.

Get immediate medical attention

It’s critical to get medical attention when you think you’re having a flare-up, or if you haven’t previously received a diagnosis of GPP and think you may be having your first flare-up.

GPP is difficult to diagnose due to its rarity and lack of standardized international diagnostic criteria.

The Japanese Dermatological Association and the Study Group for Rare Intractable Skin Diseases published guidelines in 2018 for diagnosing GPP. Their diagnostic criteria are:

  1. systemic symptoms, such as fever or fatigue
  2. extensive skin flushing with multiple pus-filled bumps
  3. pus-filled bumps characteristic of GPP
  4. repeated flare-ups of the above findings

A definitive diagnosis can be made if you have all four features. GPP would be highly suspected if you have features 2 and 3.

Doctors also order blood or urine tests to look for signs of inflammation or other complications.

GPP can be a substantial source of emotional and physical discomfort. Most people with GPP have recurrent flare-ups ranging from weeks to years apart. In a 2022 study, researchers found that only about a third of people with GPP they surveyed felt that their condition was well controlled.

The outlook for people with GPP seems to be best when there’s a clear trigger. Keeping a diary to track potential triggers can help you reduce future flare-ups and improve your quality of life.

The development of new treatments for GPP may significantly increase the outlook in the future.

GPP is a type of psoriasis that causes pus-filled bumps to form on a large part of your skin. It’s very rare and can cause life threatening complications. It’s not exactly clear what causes it but it’s thought that a combination of genetic factors and environmental triggers play a role.

It’s critical to get immediate medical attention whenever you’re experiencing a GPP flare-up. Your healthcare team can help you manage your symptoms and minimize your chances of developing complications.

As of November 2022, only one medication is FDA approved to treat GPP, but many other medications are used as off-label treatments.