What Is Palmoplantar Psoriasis and How Is It Treated?

Palmoplantar psoriasis is a form of psoriasis confined to the palms of the hands and the soles of the feet, and it tends to be more disabling than psoriasis elsewhere on the body. People with palmoplantar involvement report roughly twice the odds of problems with mobility, self-care, and daily activities compared to those with moderate-to-severe plaque psoriasis on other body sites. Despite affecting a relatively small surface area, the condition strikes exactly the skin you need most for gripping, walking, and working, which is part of what makes it so disproportionately burdensome and so stubbornly difficult to treat.

Why It Hits Harder Than Other Forms of Psoriasis

Psoriasis severity scores are typically tied to how much body surface area is affected. By that measure, palmoplantar psoriasis looks mild on paper. But research consistently shows that patients with this subtype experience greater physical disability and discomfort than those whose psoriasis spares the hands and feet.¹ The thick, cracked skin on the palms and soles can make it painful to hold objects, stand for extended periods, or even put on shoes. Fissures that open during everyday movements bleed and sting, and the constant visibility on the hands adds a layer of social embarrassment.

A study comparing quality-of-life scores found that the adjusted odds of reporting at least a moderate impact on skin-specific quality of life were about twice as high for patients with palmoplantar psoriasis as for those with plaque psoriasis elsewhere. Self-care difficulties were roughly three times more likely, and problems with usual activities about two and a half times more likely.² These numbers help explain why dermatologists often escalate treatment sooner for palmoplantar disease than for a similar-sized patch on, say, the trunk.

What It Looks Like and How It Gets Diagnosed

Palmoplantar psoriasis can present as thickened, scaling plaques on the palms or soles, sometimes with painful fissures running through them. In some people, it shows up as crops of small sterile pustules rather than plaques, and the two patterns can overlap. The skin on the palms and soles is already much thicker than elsewhere, which changes the appearance from what most people picture when they think of psoriasis. Classic silvery scales may be less prominent, replaced instead by a yellowish, waxy thickening.

Diagnosis can be tricky because several other conditions produce similar-looking changes on the hands and feet. Chronic hand eczema, fungal infections of the palms or soles, and allergic contact dermatitis can all mimic palmoplantar psoriasis. Dermoscopy, which uses a magnifying lens with polarized light, has become a useful bedside tool for telling these apart. Specific vascular patterns and scale characteristics visible under dermoscopy can help clinicians distinguish palmoplantar psoriasis from fungal infection and eczema without needing a biopsy in every case.³

When a biopsy is performed, the microscopic findings have their own quirks. In a case series of 21 palmoplantar psoriasis biopsies, all showed alternating zones of abnormal and normal surface skin cells, and about nine in ten had a reduced or absent granular layer, a hallmark feature. However, the spongiform pustules often described in textbook psoriasis appeared in only a small fraction of samples, which can make histologic confirmation less straightforward than for plaque psoriasis on the body.⁴

The Classification Tangle

If you start reading about palmoplantar psoriasis, you will quickly encounter a confusing overlap with something called palmoplantar pustulosis. Whether these are the same disease, related diseases, or entirely separate conditions is one of the longer-running debates in dermatology, and the answer partly depends on which country’s dermatologists you ask.

In Japan, most dermatologists treat palmoplantar pustulosis as a distinct entity, separate from psoriasis. Outside Japan, and particularly in European and North American practice, palmoplantar pustulosis is more commonly viewed as a variant of localized pustular psoriasis.⁵ The two conditions share a number of features: both can involve nail changes, joint symptoms, and the Koebner phenomenon (where skin lesions appear at sites of injury). A case-series study comparing the two found that existing data on genetics, clinical presentation, and the underlying disease process did not allow a clean separation, concluding that the two entities overlap considerably.⁶

This matters practically. If your dermatologist regards your palm pustules as a form of psoriasis, the treatment pathway may lean toward psoriasis-specific biologics. If they see it as palmoplantar pustulosis as a separate condition, the treatment choices and clinical trial evidence they draw on may differ. Recent molecular work has added nuance: transcriptomic studies have found that palmoplantar pustulosis and palmoplantar psoriasis share a broad overlapping inflammatory signature, including upregulation of the same proinflammatory cytokines such as TNF and IL-36.⁷ So at the molecular level, the boundaries look blurry even if the clinical traditions around naming remain sharp.

The Sweat Gland Connection

One of the more surprising findings about palmoplantar disease is the role of sweat glands. The palms and soles have far more eccrine sweat glands per square centimeter than nearly any other body region. Research has identified the acrosyringium, the part of the sweat duct that passes through the outermost layer of skin, as a key site where inflammation starts. Immunostaining shows that the cells lining the tiny blisters in palmoplantar pustulosis are actually sweat-duct cells, not ordinary skin cells.⁸

Immune cells and the inflammatory molecule IL-17 have been found clustered around these sweat duct openings, and the pattern of immune activation at the acrosyringium differs from what is seen in ordinary plaque psoriasis on the body.⁹ This sweat-gland-centered inflammation helps explain why palmoplantar disease behaves differently from psoriasis elsewhere, why it is so concentrated on the palms and soles (where sweat glands are densest), and why it is often more stubborn to treat. It also connects to the smoking story, as discussed next.

Smoking and Other Triggers

Palmoplantar pustulosis is probably the inflammatory skin disease most strongly linked to smoking. The connection is not just statistical; there is a plausible biological explanation. Sweat glands and their ducts carry nicotinic acetylcholine receptors, which respond to nicotine. In people with palmoplantar disease, these receptors show altered expression compared to healthy skin, and nicotine may amplify inflammation at the sweat duct by triggering the accumulation of immune cells in the outer skin layers.¹⁰¹¹

Quitting smoking has been shown to reduce the number of pustules, as well as the amount of scaling and redness.¹² That said, plenty of people who have never smoked develop palmoplantar psoriasis, so smoking is a significant aggravating factor rather than the sole cause.

Focal infections are another well-recognized trigger. Chronic tonsillitis, sinus infections, and dental infections have all been linked to flare-ups. Tonsillitis, in particular, is noted for triggering or worsening palmoplantar pustulosis.¹³ Dental infections are considered a major worsening factor, and roughly half of patients improve after the dental issue is treated, though a sizable number do not.¹⁴ If you have palmoplantar psoriasis that keeps flaring, it is worth mentioning to your dermatologist if you also have chronic dental problems or frequent sore throats.

Stress, mechanical irritation from repetitive friction, and certain medications can also provoke or worsen the condition. In an unusual twist, biologic medications used to treat psoriasis elsewhere on the body can sometimes paradoxically trigger new palmoplantar pustular eruptions, a phenomenon known as a paradoxical adverse event.¹⁵

Who Gets It

Palmoplantar psoriasis accounts for a meaningful share of all psoriasis cases. One clinical study found a prevalence of about 15% among all psoriasis patients seen in the clinic.¹⁶ The demographic profile depends partly on whether you are looking at the plaque type or the pustular type. For palmoplantar psoriasis overall, some datasets show a male predominance, while palmoplantar pustulosis tends to affect more women than men. A large Japanese claims database found that about two-thirds of palmoplantar pustulosis patients were female, with peak prevalence in the late 50s for women and early 60s for men.¹⁷

The prevalence of palmoplantar pustulosis is higher in Japan than in the United States, and rates have been increasing over time in the databases that have tracked it.¹⁸ Whether this reflects genuine differences in genetic susceptibility, smoking patterns, environmental exposures, or simply diagnostic habits across countries is not fully clear.

Treatment Options

Treating palmoplantar psoriasis is notoriously challenging. The thick stratum corneum on the palms and soles acts as a barrier to topical medications, and the constant mechanical stress of walking and gripping works against healing. Clinicians have long noted that palmoplantar sites are among the most resistant to standard psoriasis therapies, and there is still no consensus on the best treatment approach.¹⁹

Topical and Light-Based Therapies

First-line treatment usually involves potent topical corticosteroids, often under occlusion (wrapping the hands or feet after applying the cream to increase penetration). Vitamin D analogues and coal tar preparations are also used. For many people, topicals alone are not enough because of the barrier thickness, but they can help manage milder disease and are commonly combined with other treatments.

Phototherapy is another option for palmoplantar disease. Targeted ultraviolet light can be directed at the palms and soles without exposing the whole body. A trial comparing 308-nm excimer light with cream PUVA (a combination of a light-sensitizing agent applied to the skin followed by UVA exposure) found that both achieved roughly the same degree of improvement, around 63 to 65% reduction in severity scores.²⁰ The advantage of excimer light is that it avoids the photosensitizing cream and delivers the UV dose only to affected skin, reducing side effects.

Systemic Medications

When topicals and phototherapy fall short, systemic medications become necessary. Three traditional options are methotrexate, acitretin (a retinoid), and cyclosporine. A head-to-head trial of methotrexate versus acitretin in palmoplantar psoriasis found that a 75% improvement in severity was achieved in about a quarter of methotrexate patients compared to 8% of those on acitretin, a statistically significant difference favoring methotrexate.²¹

A three-arm trial comparing all three drugs told a more nuanced story. Cyclosporine cleared lesions fastest and achieved the lowest severity scores at the end of treatment. But once treatment stopped, acitretin maintained remission the longest, averaging about nine weeks, compared to about six and a half weeks for cyclosporine and just three weeks for methotrexate. Side effects were more common with acitretin (dry lips, elevated lipids, hair thinning) than with the other two drugs.²² In practice, the choice among these drugs depends on the patient’s other health conditions, how quickly they need relief, and how long they can safely stay on the medication.

Biologics

Biologic therapies, which target specific immune molecules rather than suppressing the immune system broadly, are increasingly used for palmoplantar disease that does not respond to older treatments. A review of the evidence found that secukinumab (which blocks IL-17) and guselkumab (which blocks IL-23) have shown the best results among biologics tested in trials for palmoplantar pustulosis.²³ Other targets being studied include IL-36, which figures prominently in the shared inflammatory signature of palmoplantar diseases. Genetic research has identified mutations in several genes, including IL36RN, that predispose people to pustular psoriasis, and drugs aimed at these pathways are in development.²⁴

One complication worth knowing about: as mentioned in the triggers section, biologic drugs that work well for plaque psoriasis can occasionally set off a paradoxical palmoplantar pustular reaction. If you develop new palm or sole symptoms while on a biologic for psoriasis elsewhere, your dermatologist needs to know. Switching to a biologic with a different mechanism has resolved the problem in reported cases.

Measuring Severity

Because standard psoriasis scoring tools (like the PASI, which weights body surface area heavily) undercount the impact of palmoplantar disease, dermatologists have developed a modified version called the m-PPPASI, specifically designed for palms and soles. Validation work has shown it to be reliable across different clinicians and responsive to treatment changes. The scoring tool categorizes disease as mild, moderate, severe, or very severe based on cutoff points that align with quality-of-life impact.²⁵ If your doctor seems to be minimizing the severity of your palmoplantar psoriasis because it only covers a small body area, it is reasonable to ask whether they are using a palmoplantar-specific assessment.

SAPHO Syndrome and Joint Involvement

A subset of people with palmoplantar pustulosis develop bone and joint problems that go well beyond the occasional sore knee. SAPHO syndrome, which stands for synovitis, acne, pustulosis, hyperostosis, and osteitis, is a condition characterized by chronic inflammation of bones and joints alongside skin eruptions, most commonly palmoplantar pustulosis.²⁶ The chest wall, particularly the sternoclavicular region, is a classic site of bone involvement, and patients sometimes present with unexplained chest or collarbone pain before the skin diagnosis is even considered.²⁷

SAPHO is often delayed in diagnosis because few clinicians see it regularly, and its symptoms can be mistaken for infection or other inflammatory arthritis. If you have palmoplantar pustulosis along with persistent bone or joint pain, especially in the front of the chest, raising the possibility of SAPHO with your doctor could save months of diagnostic wandering. The condition responds to different treatment strategies than psoriasis alone, including bisphosphonates and anti-TNF agents, so getting the right diagnosis changes the management plan considerably.