Palmoplantar psoriasis: psoriasis of the palms and soles

Psoriasis is a common skin condition. The NHS describes it as causing itchy and painful patches of dry, flaky skin, and says it cannot be cured but treatments can help to manage the symptoms. The NHS also notes that you may get lots of small brown and yellow spots on the palms of your hands and soles of your feet.

Palmoplantar psoriasis is the name used when psoriasis is concentrated on those sites, where the skin is thick and under constant friction and pressure. Two broad patterns are recognised. In one, the skin becomes red, dry, thickened and scaly with painful cracks (fissures), similar to plaque psoriasis elsewhere. In the other, called palmoplantar pustulosis or pustular palmoplantar psoriasis, fluid-filled blisters (pustules) appear on the palms and soles. The British Association of Dermatologists (BAD) leaflet used for this page covers the pustular form and describes it as a form of psoriasis, with up to 24% of patients also having psoriasis on other parts of the body.

According to the BAD leaflet for the pustular form, the skin of the palms and soles can be very itchy and painful, particularly if there are deep cracks. It often affects both sides symmetrically but can occur on just one side. During flare-ups the skin is red with tiny blisters filled with yellow or white fluid, which turn brown and become scaly. In the more persistent stage the skin can be dry and thickened and develop painful fissures. One or more nails can become thicker, discoloured, ridged or pitted, and may separate from the nail bed.

A GP notebook entry for clinicians says pustular palmoplantar psoriasis is commonly seen in women, presents between the ages of 40 and 60 and is uncomfortable or painful rather than itchy, with psoriatic nail involvement commonly seen. The BAD leaflet says it is rare in children.

The BAD leaflet says the exact cause is still not fully understood. It is described as an auto-inflammatory disease. Smoking is one of the most common causes of development of the pustular form. Several other factors are known to make some people more likely to be affected, including metal sensitivities (mainly nickel), infections, trauma, stress and some medications. Some psoriasis treatments known as TNF-alpha antagonists may occasionally trigger it, though many other psoriasis treatments improve it.

It is more common in people who have other autoimmune conditions such as arthritis, diabetes, thyroid disorders or coeliac disease, and people with a family history of psoriasis are more likely to be affected, although most patients have no other affected family members. The NHS also advises seeing a GP if psoriasis comes with joint pain, stiffness and swelling that keeps coming back, as some people develop psoriatic arthritis.

The BAD leaflet says that in most cases the diagnosis is made by a doctor taking a history and looking at the skin. Because a fungal infection can look very similar, a doctor may take a painless skin scrape to check for it, and a swab of the fluid inside pustules to rule out bacterial infection. Sometimes a small biopsy under local anaesthetic is needed.

Because other conditions such as fungal infection can look similar, a GP may refer you to a dermatologist if the diagnosis is uncertain or treatment is not working. The NHS advises seeing a GP if you have symptoms of psoriasis or your treatment is not working or is giving you side effects.

The BAD leaflet describes a stepped approach tailored to the severity of the condition, which often changes over time.

• Moisturisers applied several times a day, with greasier ointments advised for most people, as a barrier and to reduce dryness and itching.

• Steroid creams and ointments, more effective when used under occlusion such as a waterproof dressing, vinyl gloves or cling film, and steroid tapes for cracks. Skin can get used to steroids so continuous use may be less effective.

• Tar ointments, sometimes combined with steroid and salicylic acid.

• Light treatment: PUVA and re-PUVA with ultraviolet light A given twice weekly at a dermatology department for at least 10 weeks.

• Tablets: acitretin (not usually recommended for women of childbearing age because pregnancy must be avoided during and for 3 years after treatment), alitretinoin, methotrexate and ciclosporin.

• Biologic injections, currently used only for very severe disease when standard treatments are unsuitable or have failed.

The BAD leaflet recommends stopping smoking if you smoke, using a moisturising cream or ointment instead of soap, bubble bath or shower gel, applying moisturiser several times a day, wearing protective gloves for wet work and chemicals, resting sore hands and feet where possible, wearing cotton or very soft synthetic socks and shoes, and avoiding wool. Cotton gloves and socks at night over ointments can reduce transfer to bed linen. Thickened skin cracks more easily, and applying salicylic acid or urea creams can reduce it. A podiatrist can offer foot care advice.

The NHS notes that living with psoriasis can be difficult, and that if it affects your mental health you may be referred to a mental health specialist. The BAD leaflet says the pain and itch can make it hard to walk comfortably or use the hands, and can affect sleep, work and daily activities, so tell your clinician how it is affecting you.

The NHS says to call 999 or go to A&E if you have psoriasis and your skin quickly turns red with white pus-filled bumps that join together, patches on your feet that turn yellow-brown and are filled with pus, or red scaly pus-filled bumps on the tips of fingers and toes, particularly with a fast heartbeat, high temperature or feeling hot, cold or shivery.

On the NHS, treatment starts with a GP and goes to a dermatology department for light therapy, tablets or injections. Private dermatology appointments can offer quicker review, but phototherapy courses and biologic treatments are delivered through specialist units, and the treatment ladder described above is the same.