Generalized pustular psoriasis causes pus-filled bumps and redness across a large amount of your skin.

Generalized pustular psoriasis (GPP) is a rare type of psoriasis that causes pus-filled bumps and redness across a large amount of your skin. In severe cases, more than 75% of your skin can be affected.

According to the National Psoriasis Foundation, a GPP flare-up tends to last for a few weeks followed by a period of remission where your skin partially or completely heals.

Flare-ups often cause general symptoms like fever and chills and can lead to life threatening complications like heart, kidney, or lung failure.

GPP and other forms of psoriasis develop when immune system dysregulation leads to increased inflammation and an accumulation of white blood cells in the skin. It’s not clear why this happens, but it’s thought that a combination of genetics and environmental triggers plays a role.

Keep reading to learn more about what GPP looks like and what types of symptoms it causes.

The first sign of GPP is usually inflamed and red skin that’s tender or itchy. Small pus-filled bumps called pustules appear within about 2 to 3 hours. These bumps can merge and cause large areas of pus sometimes referred to as “lakes of pus.”

Pustules dry out in the days to weeks following a flare-up and may turn red and peel.

Here are some examples of what GPP looks like.

GPP is characterized by pus-filled bumps over a large area of your body. Affected areas of skin may also be:

  • red
  • painful
  • tender
  • itchy

The Japanese Dermatological Association severity index classifies GPP based on the percentage of your skin affected:

SeverityPercentage of your skin
mildfewer than 25%
moderatebetween 25% to 75%
severemore than 75%

People with GPP often also develop symptoms affecting other body systems. These symptoms include:

It’s important to contact a doctor if you think you may have psoriasis but don’t have a diagnosis. A doctor can help you rule out other conditions that may be causing your symptoms and help you develop a treatment plan.

Medical emergency

GPP can cause life threatening complications. If you think you might be having a GPP flare-up, it’s critical to get immediate medical attention. GPP can affect people of all ages, but it’s most common in people between the ages of 40 to 59. Call emergency medical services or go to the nearest emergency room if you experience any severe symptoms.

The World Health Organization lists two other types of pustular psoriasis in its “International Classification of Diseases 11th Revision.”

Palmoplantar pustulosis

Palmoplantar pustulosis causes pus-filled bumps on the palms of your hands and the soles of your feet. About 16% of people also have psoriasis elsewhere on their bodies.

The majority of people with palmoplantar pustulosis are smokers or former smokers. It’s speculated that smoking may activate nicotine receptors on your hands and feet that cause an inflammatory response and triggers palmoplantar pustulosis.

Acropustulosis of Hallopeau

Acropustulosis of Hallopeau causes pus-filled blisters on your fingers and toes. It’s often triggered by trauma or infection at the tip of one of your fingers or toes. In about 80% of cases, it starts on one finger or toe. The thumb is most commonly affected.

Variants of GPP

GPP can be further subdivided into categories depending on its features:

  • Von Zumbusch subtype: GPP associated with systemic symptoms like joint pain or fever
  • Annular subtype: GPP that causes round rashes with pus-filled blisters along the edges
  • Exanthematic subtype: GPP without systemic symptoms like fever or joint pain
  • Impetigo herpetiformis: GPP occurring during pregnancy

Here are some frequently asked questions that people have about GPP.

How rare is generalized pustular psoriasis?

GPP is rare, but it’s not exactly clear how many people it affects since it’s frequently misdiagnosed. Based on the results of surveys in Japan and France, researchers estimated GPP affects 1.76 and 7.46 people per million in these countries, respectively.

Research analyzing South Korean insurance data estimate GPP affects 88 to 124 people per million.

Is generalized pustular psoriasis hereditary?

Researchers aren’t exactly sure what causes GPP, but it’s thought that a combination of genetic factors and environmental triggers play a role in its development. Sometimes, GPP is associated with genetic mutations passed through families.

Mutations in the IL-36RN gene are the most frequent genetic abnormalities seen in people with GPP.

Does generalized pustular psoriasis go away?

GPP causes recurrent flare-ups that can cause pus-filled blisters that last for months. These flare-ups often occur over a lifetime.

How is generalized pustular psoriasis treated?

Spevigo became the first medication approved by the Food and Drug Administration for treating GPP in September 2022. This medication is administered through an IV to block the inflammatory pathway that leads to GPP symptoms.

Researchers are continuing to investigate the effectiveness of other medications. Imsidolimab was in stage 3 clinical trials as of December 2022.

GPP is a rare type of psoriasis that causes pus-pilled blisters to form over a large part of the body. It can cause life threatening side effects like heart or lung failure and flare-ups require immediate medical attention.