Eczema is a condition that generally refers to any skin inflammation. It is characterized by itching, redness, dryness and scaly vesicular lesions. Dyshidrotic eczema, or simply dyshidrosis, is a recurrent and chronic type of eczema characterized by outgrowths of small, bubble-like lesions called vesicles in the palms and fingers. Because of the appearance of the skin lesions in dyshidrosis, the condition is also called pompholyx or cheiropompholyx, which was derived from Greek words that mean “hand and bubble.” If you have dyshidrosis, you may have symptoms of food allergies and asthma.
Classically, dyshidrosis is believed to be due to the dysfunction of eccrine sweat glands in the skin, with the vesicular lesions thought to represent the dysfunctional sweat ducts. Several studies, however, dispute this hypothesis because histological analyses of dyshidrotic eczematous lesions do not show any association with sweat glands and ducts. Nevertheless, it is recognized that excessive sweating in the hands--a condition known as hyperhidrosis--aggravates dyshidrosis.
The cause of dyshidrotic eczema is most likely multifactorial in nature and is due to an interplay between various endogenous and exogenous factors. Genetics is possibly the strongest endogenous risk factor for dyshidrotic eczema, with strong associations between dyshidrosis and a history of atopy in the family. Among exogenous factors are sensitivity to metals such as nickel and cobalt, skin fungal and bacterial infections, emotional stress, seasonal changes and humidity.
Dyshidrosis is one of the more common forms of eczema affecting the hands. Both sexes and generally all age groups are affected. Dyshidrosis most frequently affects children to middle adults, and the incidence of the condition tends to decrease after middle age.
Signs and Symptoms
The most common presentation of dyshidrosis is a sudden eruption of vesicles over the palms, soles, and sides of the fingers and toes, accompanied or preceded by severe itchiness or a burning sensation. Unlike other types of eczema, the lesions of dyshidrosis are neither red nor surrounded by an area of redness. Factors related to the eruption of vesicles include skin infections, emotional stress, and exposure to contact allergens and irritants.
The vesicles of dyshidrosis contain a clear liquid and occur in crops, resembling tapioca. Sometimes small vesicles coalesce to form larger bubbles called bullae. In other cases, vesicles and bullae may become secondarily infected by bacteria, suppurate, and, in severe cases, even progress to inflammation of the surrounding soft tissue and lymphatics. With long-standing disease, the nails can also be affected and show ridging, pitting or discoloration.
Oftentimes, the vesicles of dyshidrosis spontaneously resolve without rupturing. Resolution of lesions is followed shortly by desquamation and peeling of affected areas.
Mild cases of dyshidrosis spontaneously resolve after two to three weeks. However, for cases that do require treatment, steroid creams and ointments comprise first-line medications. Especially in exceptionally severe cases of dyshidrosis, oral prednisone may need to be used.
Other forms of treatment include topical immunomodulators such as tacrolimus and pimecrolimus, ultraviolet therapy with psoralens and intradermal injections of botulinum toxin A. Dyshidrosis that does not respond to conventional treatment may need immunosuppresants such as azathioprine, methotrexate, mycophenolate, cyclosporine and etanercept.