This is an affliction that occurs among beekeepers because of their contact with propolis. I personally have only become susceptible to this ailment a few years ago. I will explain how I believe it happened...
Some time ago I was selecting some blocks of beeswax for making candles. I noticed a flake of propolis stuck to the surface of one of these blocks and I scraped it off using a fingernail. I was overzealous in the application of pressure and a piece of beeswax and the propolis forced my fingernail from the fleshy tip of my finger. This was extremely painful, I removed the wax and used a sticking plaster to hold the nail in place. Healing did not occur and so I started treating the gap between the nail and the flesh with tincture of propolis, simply because I had found this to accelerate healing in the past.
At some stage I noticed a rawness in the 'V' between my fingers and it was pointed out to me that this was 'Beekeeper's Dermatitis' and that it was an allergy to propolis. I stopped using the tincture of propolis on my fingernail which is now healing, but at a very slow pace compared to normal. Healing has now completed (July 2002), but took about 3 years.
The Drawing at left is only an approximation, however it gives an indication of what the problem looks like, in spite of my lack of drawing skills.
The red area in the 'V' of the fingers is raw and blistered, but does not cause pain. I have never considered it to be a major affliction, it looks worse than it feels. Contact with propolis causes an increase in the raw areas between the fingers.
I consider that sweating inside propolis impregnated leather beekeeping gloves has not improved the condition either.
There is some suggestion that susceptibility to... Hay fever, allergic rhinitis, and asthma is also an indicator of susceptibility to dermatitis. However this link to my mind is, as yet, unproven, even though I suffer from all of them.
There is also some conjecture that Colloidal Silver, is of some use in combating dermatitis. It is claimed that it does so safely and in a short time, with no side effects or resistant strains, as can happen with antibiotics.
Colloidal Silver is growing in use for swimming pool treatment, also in agriculture and industry to kill fungi and bacteria.