What Triggers Dyshidrotic Eczema?

Itchy blisters on the soles of the feet are a sign of dyshidrotic eczema.

Dyshidrotic eczema (also called pompholyx or acute and recurrent vesicular hand dermatitis) is a skin condition characterized by small, intensely itchy blisters on the edges of the fingers, toes, palms of the hands, and soles of the feet.

Dyshidrotic eczema may be acute, recurrent, or chronic. It affects teenagers and adults, and it is twice as common in women as in men.

The severity of dyshidrotic eczema (pompholyx) symptoms can vary widely from minor to debilitating. The condition tends to be chronic and intermittent, and episodes occur less frequently with age.

Symptoms and signs of dyshidrotic eczema include the following:

• Small, symmetrical blisters may form on the edges of the fingers, toes, palms of the hands, and soles of the feet. The blisters have the following characteristics:
  • Itch intensely
  • May become large, fluid-filled, and join together
  • In chronic disease, fingernails may reveal degenerative changes such as ridges, thickening, discoloration, and pitting.
  • Blisters typically heal on their own without rupturing, followed by skin peeling.
• Skin redness
• Flaking
• Scaly, cracked skin
• Pain

Atopic dermatitis and contact dermatitis may look like dyshidrotic eczema.

The cause of dyshidrotic eczema (pompholyx) is unknown, but it is most likely due to several factors. A history of atopic dermatitis is a risk factor for developing dyshidrotic eczema.

Common triggers for dyshidrotic eczema include the following:

• Exposure to contact allergens or irritants, particularly metals such as nickel or cobalt
• Exposure to contact irritants, such as chromium salts used in manufacturing
• Fungal infection
• Recent treatment with intravenous immune globulin
• Smoking
• Exposure to ultraviolet (UV) radiation
• Stress
• Pollen
• Excessive sweating or prolonged contact with water
• Human immunodeficiency virus (HIV) infection

Doctors make a diagnosis of dyshidrotic eczema (pompholyx) following a history and physical exam. Blood tests usually are not necessary. Tests to confirm a diagnosis or rule out other conditions may include

• bacterial culture and sensitivity,
• patch testing,
• KOH wet mount, and
• punch biopsy for direct immunofluorescence.

Dyshidrotic eczema (pompholyx) is typically chronic and recurrent, though episodes occur less frequently with age and most patients eventually go into complete remission. Dyshidrotic eczema may become infected.

Treatment aims to relieve symptoms and signs and includes the following:

• High-strength topical steroids and/or systemic steroids for itching
• Drainage of large blisters (bullae): systemic antibiotics prescribed that cover Staphylococcus aureus and group A streptococci to prevent infection
• UVA or UVA-1 alone or with oral or topical psoralen
• Topical calcineurin inhibitors
• OnabotulinumtoxinA injections (Botox)
• For severe cases: azathioprine, methotrexate, mycophenolate mofetil, cyclosporine, or etanercept
• Alitretinoin (9-cis retinoic acid)
• Nickel chelators (for example, disulfiram) may be used in nickel-sensitive patients.

Home treatments for dyshidrotic eczema include the following:

• Cold compresses applied for 15 minutes to affected areas two to four times a day followed by a rich moisturizer or a skin barrier repair cream
• Soak hands and feet in cool water
• Compresses with Burow solution or 1:10.000 solution of potassium permanganate for blisters
• Bed rest if there are large blisters on the feet
• Avoid dietary sources of nickel and cobalt in the nickel- and cobalt-sensitive patient
  • Food sources of nickel include chocolate, cocoa, oatmeal, nuts, almonds, soybeans, fresh and dried legumes, and canned foods.
  • Food sources of cobalt include fish, clams, oysters, liver, leafy green vegetables, milk, nuts, and red meat.

Stress-reduction techniques and counseling or biofeedback may help some patients cope with symptoms and signs.

Complications of dyshidrotic eczema (pompholyx) include secondary bacterial infection of the blisters, which may result in cellulitis, lymphangitis, and septicemia (rare).

Degenerative nail changes may occur such as

• transverse ridging,
• thickening,
• discoloration, and
• pitting.

If large blisters develop on the hands, patients may not be able to work or perform other daily activities.

In severe cases, dyshidrotic eczema can become debilitating.

For the most part, it's not possible to prevent dyshidrotic eczema (pompholyx). If there are known triggers, avoid them. Consistent and proper skin care with moisturizing may help keep skin healthy and minimize flares.

Consultation with an allergist may be helpful if triggers are due to allergies to nickel, cobalt, or chromium salts.