I had these between my fingers for several years when I had a very stressful job; it always appeared in late spring with the arrival of warm weather. My dermatologist prescribed hydrocortisone cream which did little to relieve the itching and did not help to heal the lesions. The condition I had is called dyshidrosis or dysidrotic eczema and there seems to be no agreement on the cause which is listed as unknown, allergic, stress-related or linked to fatigue. It is usually aggravated by humidity Transparent blisters containing a watery substance form on the skin between fingers or toes; it is accompanied by a burning sensation and itching. In my case, it seemed to be an allergic reaction aggravated by stress which depletes the body's natural supply of antihistamines. I was able to get rid of the blisters in 24 hours with a homeopathic remedy which I will list below for anyone who wants to try it. If homeopathy wasn't available I would probably try clay or castor oil packs and drink clay water which is made with 1 tsp. green clay powder in a large glass of water--stirred with a wooden spoon--left overnight. In the morning, drink only the water and pour the remaining clay in your flower pots. This by the way is a very inexpensive way and easy way to remove toxins, including heavy metals, from the body. It does take patience. In the same vein I would try things to reduce acidity, like drinking kombucha, taking a few drops of stabilized oxygen several times a day in a glass of water, petting my cat, deep breathing, etc.
Hydrogen peroxide has given relief to some. This treatment is described in detail at http://www.geocities.com/vyera/dyshidrosis/main.html There even seems to be a forum for dyshidrosis. ** The treatment for dyshidrosis from the homeopathic dictionary by Louis Pommier: Sulfur 4CH alternately with Rhus tox. 5CH (two grain doses); Primula obconica 4CH and Anagallis arvensis 4CH--two grains of each every 24 hours. He recommends almond oil as a moisturizer. I always have these on hand; I have never taken them more than two days before the symptoms disappeared. I hope this information helps. I remember how painful it was. Blessings, Carlene