It does sound like it could be an allergic reaction to something she works with. Unfortunately the best treatments for that sort of reaction are to avoid exposure to whatever is causing the problem. Which is hard when it's part of your job. It would be worth trying to isolate what is the problem (maybe during a holiday from work?) and maybe change to a different product/brand which doesn't cause problems. It could be a reaction to other things though, even though it's only on the hands - foods, cosmetics (including moisturisers!!), medications... all common culprits.

There are lots of steroid creams that doctors can prescribe but there are also over the counter things that can help with that sort of skin reaction - avoiding soap is a very important one as soap is the wrong pH for skin and is quite drying as a result. Soap/fragrance free washes (Cetaphil is my favourite, but there are a few out there - the other Australian brands don't appear to be available overseas) are great. And a heavy duty moisturiser is also vital. Sorbolene/cetomacrogol is not good enough (it's more used as a base for other ingredients like sulfur, salicylic acid etc). Cetaphil makes one which I recommend a lot. And usually the companies that make the soap free/fragrance free washes make them too. Avoiding overly hot water is also a good plan. And it's a good idea to either wear (lines) gloves or get someone else to do the washing up (hot water plus detergent = bad).

A dermatologist consultation is very important though, to work out what is causing the problem and how to best treat it.