Dyshidrosis, also known as dyshidrotic eczema or pompholyx, is a skin condition in which small, fluid-filled blisters (vesicles) occur on the palms of your hands or the soles of your feet, or both.
The blisters that occur in dyshidrosis last up to three or four weeks, and cause intense itching. Once the blisters dry, cracks and grooves (fissures) form, which can be painful.
The cause of dyshidrosis isn't known. Treatment for dyshidrosis most often includes topical creams, wet compresses and ultraviolet light therapy. Even with treatment, recurrence of dyshidrosis is common.
Signs and symptoms
Dyshidrosis is marked by small, itchy bumps that gradually progress to a rash made up of fluid-filled blisters (vesicles). Other signs and symptoms may include:
* Intense itching
* Cracks or grooves (fissures) on your fingers or toes
* Pain, especially with large blisters
The cause of dyshidrosis is unknown. However, it can be associated with a similar skin disorder called atopic dermatitis and other allergic conditions, such as asthma and hay fever (allergic rhinitis). Eruptions may be seasonal in people with allergies.
In dyshidrosis, the affected skin becomes inflamed (dermatitis). As a result, the junctions between the skin cells open and allow fluid (serum) to fill the spaces. Doctors refer to this process as spongiosis because the skin becomes more sponge-like with these many fluid-filled spaces.
The resulting small, fluid-filled blisters (vesicles) most commonly occur on the palms and fingers of your hands and on the soles and toes of your feet. The blisters usually last for three to four weeks.
The blisters often cause intense itching. Scratching the blisters can damage the skin and, in some cases, lead to infection. Once the blisters dry, they often leave cracks and painful grooves (fissures) in your skin.
Dyshidrosis occurs twice as often in women as in men. Other risk factors include:
* Stress, because dyshidrosis appears to be more common during times of stress
* Exposure to metal salts, such as chromium, cobalt and nickel — usually through cement or mechanical work
* Having seasonal allergies, such as hay fever
* Frequently exposing your skin to water or other wet substances
When to seek medical advice
Call your doctor if you have a rash on your hands or feet that doesn't go away on its own after a few days.
Also contact your doctor if you've been diagnosed with dyshidrosis and have signs and symptoms of an infection, including fever, or pain or inflammation at the rash site.
Screening and diagnosis
In most cases, your doctor can diagnose dyshidrosis based on a physical exam.
Occasionally, a skin biopsy is necessary to confirm the diagnosis or to rule out another cause. In this test, your doctor removes a small sample of the affected skin. The skin sample is examined under a microscope to confirm a diagnosis of dyshidrosis.
Your doctor may also recommend a procedure called a KOH test to rule out other causes, such as a fungal infection. To perform a KOH test, your doctor scrapes your skin with a glass slide to collect dead skin cells. The skin cells are mixed with potassium hydroxide (KOH) and viewed under a microscope to help single out a fungal infection.
In cases where an allergy is suspected to cause dyshidrosis, a patch test (contact hypersensitivity allergy test) may help determine a possible cause. During a patch test, potential allergens are applied to a patch, which is then placed on your skin to check for a reaction.
For most people, dyshidrosis is just an itchy inconvenience. For some, however, the pain and itching may limit the use of their hands. Recurrence, which is common, can be frustrating.
In some cases, skin damage (including thickening of your skin), or a bacterial infection may occur as a result of the open, sponge-like skin or due to intense scratching. This can make treatment lengthier and more difficult.
A treatment plan for dyshidrosis may include:
* Corticosteroid creams or ointments. Your doctor may prescribe high-potency corticosteroid topical creams, such as clobetasol propionate (Temovate, others), to help speed the disappearance and improve the appearance of the blisters, and to treat the cracks and fissures that occur after the blisters have dried.
* Compresses. Wet or cold compresses can help alleviate itching, increase the effectiveness of the topical creams and minimize blisters.
* Antihistamines. Your doctor may prescribe anti-itching medications called anti-pruritics or antihistamines, such as diphenhydramine (Benadryl) or loratadine (Claritin), to help alleviate itching.
If these treatments aren't effective, your doctor may recommend a special kind of ultraviolet light therapy called psoralen plus ultraviolet A (PUVA). This treatment combines exposure to ultraviolet light (phototherapy) with drugs that help make your skin more receptive to the effects of ultraviolet light (psoralens).
Some doctors may consider recommending botulinum toxin injections to treat severe cases of dyshidrosis. This is a relatively new treatment option that has not yet gained acceptance among all physicians.
Recurrence of dyshidrosis is common even after treatment.
Because the cause of dyshidrosis is generally unknown, there's no proven way to prevent this condition.
However, managing stress and avoiding exposure to metal salts, such as chromium and nickel, may help prevent dyshidrosis.
If you have dyshidrosis, the following self-care measures may help:
* Avoid scratching the rash
* Limit your skin exposure to water
* Moisturize with a hand cream after washing your hands
* Take measures to protect your hands from irritants, such as perfumed lotions or dishwashing soap