- Lesions that appear on the hands and feet are very dry and often inflamed and cracked.
- Diagnosis is easier when several sites are involved.
- Palmoplantar psoriasis can have a serious impact on quality of life.
- Treatments may be local (topical), or systemic in cases which are resistant to local treatment and accompanied by lesions in other parts of the body.
What are the features of palmoplantar psoriasis?
The skin on the palms of the hands and soles of the feet is thicker than in other parts of the body. Particular types of keratin are also present, which are not found elsewhere. Lesions that appear on the hands and feet are very dry and often inflamed and cracked. Patients often experience pain.
Palmoplantar psoriasis is frequently pustular, with transparent pustules that turn white, and then form dark crusts. Generally both hands and feet are affected, but it is not uncommon for only one of these areas to be involved. When the hands are affected, lesions are only present on the palms; if plaques appear on the back of the hands, the condition is not palmoplantar psoriasis but a different type of psoriasis.
Do lesions on the hands and feet cause diagnostic problems?
It is easy to diagnose palmoplantar psoriasis when plaques are present on several sites, and in most cases, the doctor simply has to examine the lesions. However, it is sometimes difficult to differentiate psoriasis from palmoplantar pustulosis, which also affects the palms of the hands.
It can also be confused with eczema, although eczema is much more itchy than psoriasis. Eczema can produce blisters which are smaller and tend to appear between the fingers. Psoriasis of the soles of the feet can also be mistaken for a mycosis and a doctor will have tests done to see if a fungal infection is present.
In children, psoriasis may be confused with juvenile plantar dermatosis, the symptoms of which are extremely dry skin and cracks on the arch of the foot.
Is palmoplantar psoriasis very disabling?
Palmoplantar psoriasis may have a significant impact on quality of life. Lesions on the hands can lead to problems carrying out manual tasks. Even dressing can be tricky as threads catch on the skin.
Some substances, such as washing up liquid and cleaning products, irritate lesions and prevent them from healing. You should be careful not to wash your hands too often, and not to use water which is too hot, as this dries the skin.
Avoid contact with cleaning products, detergents and disinfectant as these make irritation worse. Wear gloves which are sufficiently large and lined with cotton to avoid perspiration. On the feet, cracks may be very painful. Thick socks and open shoes are recommended.
There is no reason why you should not participate in sports and physical activities. However, chlorinated water in swimming pools can lead to irritation and softening, especially if you stay in the water for too long. Sports which cause great pressure on the foot, such as tennis, can also lead to pain. You should rinse your feet in cold water and put on dry socks after exercise.
What are the main treatments for palmoplantar psoriasis?
Firstly, you should try to avoid irritating the skin of the palms and soles. Don't wash in water that is too hot, and avoid anything that causes friction to the skin.
Your doctor may prescribe hydrocolloid dressings, which are normally used to treat leg ulcers and cover the skin with a healing agent. They help lesions to heal, reduce itching and stop shoes rubbing.
Local medications, such as corticosteroids, are also available. The outermost horny layer of the skin is thicker on the palms and soles, and so medication is not as well absorbed as in other areas. This is why doctors prescribe corticosteroids to be applied under dressings in cases which resist treatment. Vitamin D derivatives and local retinoids are also sometimes administered, although their effectiveness has not been scientifically proven. Lastly, sessions of PUVA therapy may be prescribed if local treatments are not successful.
Systemic treatments are only used in palmoplantar psoriasis when it resists treatment and is accompanied by plaques in other parts of the body.
With thanks to Professor Frédéric Cambazard, Head of the Dermatology Service at the Saint-Etienne University Hospital.