Dyshidrosis is a skin condition that causes small, fluid-filled blisters to form on the palms of the hands and sides of the fingers. Sometimes the bottoms of the feet are affected too.

The blisters that occur in dyshidrosis generally last around three weeks and cause intense itching. Once the blisters of dyshidrosis dry, your skin may appear scaly. The blisters typically recur, sometimes before your skin heals completely from the previous blisters.

Treatment for dyshidrosis most often includes creams or ointments that you rub on the affected skin. In severe cases, your doctor may suggest corticosteroid pills, such as prednisone, or injections. Dyshidrosis is also called dyshidrotic eczema and pompholyx.

The blisters associated with dyshidrosis occur most commonly on the sides of the fingers and the palms. Sometimes the soles of the feet also can be affected. The blisters are usually small — about the width of a standard pencil lead — and grouped in clusters, with an appearance similar to tapioca.

In more-severe cases, the small blisters may merge to form larger blisters. Skin affected by dyshidrosis can be painful and very itchy. The blisters dry and flake off in about three weeks.

Dyshidrosis tends to recur fairly regularly for months or years.

When to see a doctor

Call your doctor if you have a rash on your hands or feet that doesn't go away on its own.

The exact cause of dyshidrosis isn't known. It can be associated with a similar skin disorder called atopic dermatitis (eczema), as well as with allergic conditions, such as hay fever. Eruptions may be seasonal in people with nasal allergies.

Risk factors for dyshidrosis include:

• Stress. Dyshidrosis appears to be more common during times of emotional or physical stress.
• Exposure to certain metals. These include cobalt and nickel — usually in an industrial setting.
• Sensitive skin. People who develop a rash after contact with certain irritants are more likely to experience dyshidrosis.
• Atopic dermatitis. Some people with atopic dermatitis may develop dyshidrotic eczema.

For most people with dyshidrosis, it's just an itchy inconvenience. For others, the pain and itching may limit the use of their hands or feet. Intense scratching can increase the risk of a bacterial infection developing in the affected skin.

Because the cause of dyshidrosis is generally unknown, there's no proven way to prevent this condition. You may help prevent the condition by managing stress and avoiding exposure to metal salts, such as cobalt and nickel.

Good skin care practices may help protect the skin as well. These include:

• Using mild cleansers and lukewarm water to wash your hands and drying your hands well
• Moisturizing regularly
• Wearing gloves

In most cases, your doctor can diagnose dyshidrosis based on a physical exam. No lab test can specifically confirm a diagnosis of dyshidrosis, but your doctor may suggest tests to rule out other skin problems that have similar symptoms.

For example, a scraping of your skin can be tested for the type of fungus that causes athlete's foot. Skin allergies and sensitivities can be revealed by exposing patches of your skin to various substances.

Depending on the severity of your signs and symptoms, treatment options may include:

• Corticosteroids. High-potency corticosteroid creams and ointments may help speed the disappearance of the blisters. Wrapping the treated area in plastic wrap can improve absorption. Moist compresses also may be applied after the application of a corticosteroid to enhance the absorption of the medication.

  In severe cases, your doctor may prescribe corticosteroid pills, such as prednisone. Long-term use of steroids can cause serious side effects.

• Phototherapy. If other treatments aren't effective, your doctor may recommend a special kind of light therapy that combines exposure to ultraviolet light with drugs that help make your skin more receptive to the effects of this type of light.
• Immune-suppressing ointments. Medications such as tacrolimus (Protopic) and pimecrolimus (Elidel) may be helpful for people who want to limit their exposure to steroids. A side effect of these drugs is an increased risk of skin infections.
• Botulinum toxin injections. Some doctors may consider recommending botulinum toxin injections to treat severe cases of dyshidrosis.

Home treatment might include:

• Applying compresses. Wet, cool compresses may help reduce itching.
• Taking anti-itch drugs. Over-the-counter antihistamine medications such as diphenhydramine (Benadryl) or loratadine (Claritin, Alavert, others) can help relieve itching.
• Applying witch hazel. Soaking the affected areas in witch hazel may speed healing.

You're likely to start by seeing your family doctor. He or she may refer you to a doctor who specializes in skin disorders (dermatologist). Here's some information to help you get ready for your appointment.

What you can do

Before your appointment, you may want to write a list that answers the following questions:

• Have you experienced this problem in the past?
• Do you have allergies to certain substances such as rubber, glues, fragrances or nickel?
• Have your stress levels worsened recently?
• What medications and supplements do you take regularly?
• Are you exposed to certain metals or chemicals in the work setting or through hobbies?

What to expect from your doctor

Your doctor is likely to ask you a number of questions, such as:

• When did you first begin experiencing symptoms?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• Are you exposed to chemicals or metals in the work setting or through a hobby?