Palmoplantar pustulosis

Pustulosis palmaris et plantaris, PPP

L40.3

Palmoplantar pustulosis is a long-lasting skin condition that causes painful, fluid-filled blisters on the palms of your hands and soles of your feet. While it shares some features with psoriasis, it is difficult to treat and can seriously affect your ability to use your hands and walk comfortably.

Table of contents

• What is palmoplantar pustulosis?
• Who gets palmoplantar pustulosis?
• What causes palmoplantar pustulosis?
• What are the symptoms and appearance?
• How is palmoplantar pustulosis diagnosed?
• How does palmoplantar pustulosis affect daily life?
• What treatments are available?
• Can palmoplantar pustulosis be cured?

What is palmoplantar pustulosis?

Palmoplantar pustulosis is a chronic skin condition that causes sterile pustules (germ-free, pus-filled blisters) to appear on the palms of your hands and the soles of your feet^[1]. The name comes from “palmo” meaning palm of the hand and “plantar” meaning sole of the foot^[2].

This condition is often considered a form of pustular psoriasis, though experts continue to debate whether it should be classified as a type of psoriasis or as a completely separate disease^[1]. It may occur alongside plaque psoriasis, but it responds less reliably to treatments that work well for regular psoriasis^[1]. A related condition that affects only the tips of the fingers and toes is called acrodermatitis continua of Hallopeau or acropustulosis^[1].

Who gets palmoplantar pustulosis?

Palmoplantar pustulosis most commonly appears in people between the ages of 20 and 60 years^[1]. Women are much more likely to develop this condition than men, with a female-to-male ratio of 4:1^[1]. The condition is rare in children^[2].

Anyone can develop palmoplantar pustulosis, but certain groups of people are at higher risk. The vast majority of patients with this condition are cigarette smokers, with 70 to 95 percent of patients being current or former smokers^[1][2]. Between 15.8 percent and 24 percent of people with palmoplantar pustulosis also have plaque psoriasis on other parts of their body^[2][3].

People who have family members with palmoplantar pustulosis or psoriasis are more likely to be affected^[2]. The condition is also more common in people who have other autoimmune conditions such as arthritis, type 2 diabetes, thyroid disorders, or coeliac disease^[2]. Other associated conditions include hypertension, hyperlipidaemia, COPD, atopic dermatitis, and depression^[1].

What causes palmoplantar pustulosis?

The exact cause of palmoplantar pustulosis remains unknown^[1]. Palmoplantar pustulosis is an auto-inflammatory disease, which means the body’s immune system mistakenly causes inflammation in healthy tissue^[2].

Smoking is one of the strongest risk factors for developing this condition^[2]. It is thought that activated nicotine receptors in the sweat glands stimulate an inflammatory process^[1]. Smoking is also a disease-aggravating factor, meaning it can make symptoms worse^[1].

Several other factors may trigger or worsen palmoplantar pustulosis. These include manual or repetitive trauma, irritants, friction, focal infections, metal allergies (mainly nickel), stress, and some medications^[1][2]. Paradoxically, some psoriasis treatments known as TNF-alpha inhibitors may occasionally trigger palmoplantar pustulosis^[1][2].

Researchers have proposed several theories about what may cause this condition. It may be a disorder of the eccrine sweat glands, which are most numerous on the palms and soles^[1]. Genetic mutations involving certain genes have been associated with the condition, though it is not associated with the major genetic markers seen in plaque psoriasis, suggesting it may be a genetically distinct condition^[1].

What are the symptoms and appearance?

Palmoplantar pustulosis usually presents as crops of sterile pustules on the palms and soles^[1]. These pustules are between 1 and 10 millimeters in size and often appear alongside yellow-brown spots or scaly, discolored patches^[1]. The pustules first appear as tiny blisters filled with yellow or white fluid^[2].

In flare-ups, the skin becomes discolored or red, with pustules that eventually turn brown and become scaly^[2]. As the condition progresses, the skin can become dry and thickened^[2]. Lichenification (thickened, leathery skin) and desquamation (peeling skin) are commonly seen^[1].

Pustules are most commonly found on the thenar and hypothenar eminences (the fleshy parts at the base of the thumb and little finger) and the central palm^[1]. On the feet, they typically appear on the instep, medial and lateral borders of the foot, and the sides or back of the heel^[1].

The condition causes varying levels of itching, though a more common complaint is a burning sensation^[1]. The skin of the palms and soles can be very painful, particularly if there are deep cracks in the skin called fissures^[2]. The condition may also affect one or more nails, causing them to become thicker, discolored, develop ridges and pitting, and sometimes separate from the nail bed^[2].

Often the inflammation of the skin on the palms and soles is symmetrical, but it can occur on just one side^[2]. The condition is persistent, but symptoms can vary, becoming better and worse over time, often with no obvious cause^[2].

How is palmoplantar pustulosis diagnosed?

In most cases, the diagnosis is made by a doctor after taking a medical history and by simply looking at a person’s skin^[2]. However, because palmoplantar pustulosis can resemble other skin conditions, additional tests may be needed.

Since a fungal infection can look very similar, a doctor may take a painless skin scrape to check for this^[2]. A painless swab of the fluid inside the pustules may be taken to rule out a bacterial infection^[2].

Sometimes a small biopsy may be needed to confirm the diagnosis^[2]. This requires a local anaesthetic injection into an affected area and the removal of a small piece of skin to look at under the microscope^[2]. This is followed by stitches to close the wound, after which the area should heal with a small scar^[2].

How does palmoplantar pustulosis affect daily life?

Although the condition is not cancerous or contagious, the inflammation of the palms and soles can severely affect one’s quality of life^[2]. Palmoplantar pustulosis can be one of the most disabling forms of psoriasis because it can limit the use of your hands and feet^[11].

The painful cracks and lesions can make daily activities such as walking, standing, and using your hands difficult^[2]. It can make it hard to walk comfortably or to use your hands without pain, possibly affecting sleep, work, and activities of daily living^[2]. Daily activities such as holding objects, typing, or walking can become painful^[11].

What treatments are available?

Like many skin conditions, palmoplantar pustulosis cannot be cured^[2]. However, there are several treatment options which can improve it significantly^[2]. Treatment of palmoplantar pustulosis is challenging, and there is no gold standard therapy^[5].

The most important first step is to stop smoking if you smoke, as this may help your symptoms get better^[6]. Basic principles of good skin care can help to reduce the frequency and severity of symptoms^[2].

Topical treatments are used as first-line therapy for mild disease. These include topical steroids (anti-inflammatory creams that can help with inflammation, swelling, tenderness, and pain), which may be used with a sterile bandage or vinyl dressing^[6]. Your healthcare provider may recommend covering the skin to make a topical treatment work better by wearing cotton or plastic gloves on the hands or cotton socks on the feet^[11]. Coal tar ointment can help heal blisters and make them less itchy, and also slows the production of skin cells^[6].

Phototherapy, particularly PUVA (treatment that uses medication along with ultraviolet light), can slow down skin growth and help with symptoms for long periods of time^[6]. Phototherapy is effective for some patients and may be used as a first-line or adjuvant treatment^[5].

For patients with moderate-to-severe disease, several systemic treatments (medications that work throughout the body) may be effective. Acitretin, which is made from vitamin A, can help manage palmoplantar pustulosis, though it can have strong side effects and is not suitable for everyone, particularly women who are pregnant or may become pregnant^[6]. Acitretin is considered the best treatment option, especially when combined with PUVA^[5].

Ciclosporin is fast acting but relapse mostly occurs immediately after stopping the medication^[5]. Methotrexate and fumaric acid show good effects and can increase the effectiveness of PUVA^[5].

Biologic treatments are given as a shot or an IV and target specific parts of the immune system^[6]. While TNF-alpha inhibitors can be efficient, an even better response can be achieved with IL-17 blockers and IL-23 blockers^[5]. Apremilast, another type of targeted treatment, may also be effective^[5].

For refractory patients or those with contraindications to use these therapies, biologic therapy may be a good option, particularly medications that block IL-17A and IL-23^[5]. Recent research is focusing on blocking the IL-36 pathway, which plays an important role in the disease, and early studies show promising results^[5].

Can palmoplantar pustulosis be cured?

There is no cure for palmoplantar pustulosis^[2]. It is a chronic condition, meaning symptoms can resolve and recur throughout a person’s life^[11]. Palmoplantar pustulosis is benign, chronic, and often relapsing^[1].

However, treatment is available to help you manage your symptoms^[11]. While there is no cure, treatments today are more effective than ever before, and research into new treatments is ongoing^[11]. Treating palmoplantar pustulosis can help improve symptoms significantly^[2].

Because the condition can sometimes be challenging to manage, it’s important to keep working with your healthcare provider until you find a treatment that works for you^[11].