If you have pustular psoriasis, you may have heard about new medicines called biologic therapies. These treatments work by targeting specific parts of your immune system that cause inflammation, helping to reduce flare-ups and improve your skin. In this article, we’ll explain what pustular psoriasis is, how it affects your body, and how biologic treatments work — so you can better understand your options and discuss them with your doctor.

What is pustular psoriasis?

Pustular psoriasis is a rare inflammatory skin condition that causes small, white or yellow blisters filled with non-infectious pus to appear on the skin.¹ These blisters are often surrounded by areas of red, inflamed skin. The condition tends to come in flare-ups, where symptoms suddenly get worse for a time before settling down. In severe cases, pustular psoriasis can cause serious complications and may even become life-threatening if not treated promptly.¹ 

What are the symptoms of pustular psoriasis?

Alongside pus-filled blisters, people with pustular psoriasis may also feel generally unwell. Common symptoms during a flare-up include a high temperature, shivering, loss of appetite, and a general sense of fatigue. These problems are caused by widespread inflammation in the body. In very severe cases, the strain on the body can lead to complications, such as heart problems, which require urgent medical care. Flare-ups can last from a few days to several weeks, and for many people, the condition returns from time to time.¹

What causes pustular psoriasis?

Doctors do not yet know the exact cause of pustular psoriasis, but certain things can trigger it in people who are already prone to the condition. These triggers can include changes in the body such as pregnancy, infections, or suddenly stopping steroid medication. Your genes can also play a role, meaning you may be more likely to develop pustular psoriasis if it runs in your family. Together, these triggers can upset the balance of the immune system, setting off inflammation that leads to the symptoms of the disease.^1,2 

How does pustular psoriasis affect the inflammatory system?

In pustular psoriasis, the immune system becomes overactive and doesn’t work as it should. Normally, your immune system protects you from illness and helps you heal after an injury by sending out “alarm signals” called cytokines. These signals tell the body to start repairing itself. In this condition, however, the body releases far too many of these signals, causing excessive inflammation. This is what leads to the redness, swelling, and other symptoms linked to pustular psoriasis.^1,2

Tumour necrosis factor-alpha (TNF-α)

TNF-α is a chemical messenger in the immune system that helps control inflammation. It works by attaching to special “receptors” on cells. Normally, the body keeps a healthy balance between inflammation and healing by using two types of receptors — one encourages inflammation when it’s needed, and the other helps to calm it down afterwards.

In pustular psoriasis, TNF-α is overproduced, pushing the immune system into overdrive. This triggers immune cells, like T-cells, to make too many skin cells (called keratinocytes), which build up and form the red, blistered patches on the skin. TNF-α can also team up with other messengers, such as IL-17 and IL-23, to keep the inflammation going, which makes symptoms worse.³ 

Interleukin 17 (IL-17)

IL-17 is another “alarm signal” produced by a type of immune cell called TH17 cells. Its job is to trigger inflammation to help fight infections and heal damage. In pustular psoriasis, however, the body makes far too much IL-17. This leads to an overproduction of skin cells, which pile up on the surface of the skin and create the painful, pus-filled blisters and redness.^3,4,5

Interleukin 23 (IL-23)

IL-23 is like the “switch” that turns on the TH17 cells, which then produce IL-17 and kick-start inflammation. In pustular psoriasis, the body makes too much IL-23, which in turn activates too many TH17 cells. This causes a chain reaction that floods the body with IL-17 and keeps the inflammation going. Doctors call this the “IL-23/IL-17 axis” — a key pathway in driving the symptoms of the disease.^4,5 

What are biologic therapies, and how are they used in pustular psoriasis?

Biologic therapies are a type of medicine designed to target specific parts of the immune system — like the TNF-α, IL-17, and IL-23 proteins we talked about earlier. Instead of suppressing the whole immune system (which can leave you more open to infections), biologics work on these precise targets to reduce the inflammation causing pustular psoriasis.

By focusing on these “troublemaker” proteins, biologics can help bring the skin symptoms under control, ease discomfort, and improve your quality of life.

Biologic therapies that target TNF-α

TNF-α is one of the main proteins driving inflammation in pustular psoriasis. Several biologic treatments work by blocking TNF-α to help calm down the immune system and reduce symptoms. Here are a few commonly used ones:

Adalimumab

Adalimumab is a biologic that blocks TNF-α from doing its job. Think of it as a shield that stops TNF-α from triggering inflammation in the skin. This helps reduce redness, blisters, and discomfort.

It’s been shown to improve symptoms for many people, and in some cases, it can even bring the condition into remission — where symptoms ease up or disappear. It can be used for both children and adults, especially when other treatments haven’t worked well enough.^3,6

Adalimumab can be used as a treatment in childhood, or as a secondary treatment when other treatments did not work.²

Etanercept

Etanercept works a bit differently. It acts like a “decoy” receptor, which means it catches the TNF-α proteins before they can cause inflammation. While the research on etanercept for pustular psoriasis is not as extensive, what we do know suggests it can be helpful for some patients.⁶ 

Infliximab

Infliximab is another treatment that targets TNF-α by preventing it from binding to receptors that cause inflammation. Clinical trials have shown infliximab to be effective and generally safe, even for children and pregnant women.⁶ 

Biologic therapies that target IL-17

IL-17 is another key protein that signals the immune system to cause inflammation in pustular psoriasis. Biologics that block IL-17 help calm this process down, reducing symptoms and helping skin heal.

Secukinumab

Secukinumab blocks a specific type of IL-17 called IL-17A. By doing this, it helps reduce the redness and pus-filled blisters that come with pustular psoriasis. It’s mainly used for moderate to severe cases and has been shown to bring about noticeable improvements. It’s also considered safe to use during pregnancy, which is good news for expecting mums.⁶ 

Brodalumab

Brodalumab works by blocking the receptor that IL-17 binds to, stopping several inflammatory signals at once. This can make a big difference in controlling symptoms. Some people taking brodalumab have reported side effects like diarrhoea or mild infections such as colds, but overall it’s an effective treatment.^6,7 

Biologic therapies that target IL-23

Guselkumab

Guselkumab is an antibody that blocks IL-23 from doing its job. This helps calm down the immune system and ease the skin symptoms. While it’s effective in general psoriasis, there isn’t a lot of evidence yet specifically for pustular psoriasis.^4,6

Tildrakizumab

Tildrakizumab works in a similar way to guselkumab, targeting the IL-23 receptor to reduce inflammation. It helps relieve symptoms and improve the skin condition in people with pustular psoriasis.^4,6

Risankizumab

Risankizumab blocks IL-23 too, preventing the activation of immune cells that cause inflammation. It has shown promising results in studies, with many patients experiencing noticeable improvement. This treatment helps manage the disease and reduce flare-ups.^4,6

Personalised medicine and caution with taking biologic therapies

While biologics offer great hope for treating pustular psoriasis, it’s important to remember that everyone’s body reacts differently. What works well for one person might not be the best for another. Some people might also experience side effects, which can sometimes be serious.

That’s why it’s really important to work closely with your healthcare team. They’ll help choose the right treatment for you, based on your individual needs.

Personalised medicine is becoming more common in treating psoriasis. This means treatments can be tailored based on your unique genetic makeup—basically, your body’s own blueprint. Scientists have found many genetic markers that help predict how the disease might behave and how you might respond to different treatments.

This approach can make treatments more effective and help avoid complications, giving you the best chance of managing your symptoms comfortably.⁸

New and upcoming treatments for pustular psoriasis

Research is always moving forward, and scientists are exploring new ways to treat pustular psoriasis. One promising area is the interleukin-36 (IL-36) pathway, which plays a part in the inflammation seen in this condition.

There are new drugs, like spesolimab and imsidolimab, that target the IL-36 receptor. Early results are hopeful, suggesting these might become useful treatments in the near future. While more studies are needed, these developments offer exciting possibilities for people living with pustular psoriasis.⁹

FAQs

What exactly causes pustular psoriasis?

Pustular psoriasis happens when the immune system becomes overactive and causes inflammation in the skin. While the exact cause isn’t fully understood, it can be triggered by things like infections, stress, pregnancy, or suddenly stopping steroid medications. Some people may also have a genetic tendency to develop it.

Are biologic therapies safe to use?

Biologics are generally considered safe and have helped many people with pustular psoriasis. However, like all medicines, they can have side effects, and not everyone responds the same way. It’s important to have regular check-ups with your healthcare team to find the best treatment for you and to monitor your health.

Can pustular psoriasis be cured?

Currently, there is no cure for pustular psoriasis, but the good news is that biologic therapies and other treatments can control the symptoms effectively. Many people live well with the condition by managing flare-ups and working closely with their doctors.

Summary

Pustular psoriasis is a rare skin condition that causes red, pus-filled blisters. It can be triggered by various factors like genetics and the environment. At the heart of the condition is an overactive immune system, which releases too many inflammatory proteins called cytokines.

Three key players in this inflammation are TNF-alpha, IL-17, and IL-23. Thankfully, modern biologic therapies can target these specifically, helping to calm the immune system without shutting it down completely.

There are several biologics available that target each of these cytokines, and they have helped many people manage their symptoms better. However, because everyone’s psoriasis is different, treatments need to be personalised, often guided by genetic testing and careful medical advice.

Ongoing research, including new drugs targeting the IL-36 pathway, promises even better options in the future. If you or someone you know is affected by pustular psoriasis, it’s important to talk to a healthcare professional about the most suitable treatment choices.