Looks like psoriasis or eczema. Its hard to pinpoint an exact cause for either since they are triggered by an immuno-response. I have palmo-plantar psoriasis which means the rash/blisters/plaques form on my hands or feet, although rarely now that I'm older and my body metabolism has changed(for me the psoriasis started when I was very young and was severe till after I got past adolescence). An outbreak could be caused by food, stress, illness or a combination of things that might cause a persons immune system to kick in and it over responds where your body starts to attack healthy cells which results in the rash. Going to a general practitioner is a waste of time. She needs to find a good dermatologist. The usual treatments include a script for some type of steroids like prednisone, some type of steroidal ointment or creme, UV light therapy, coal tar emulsion baths. Avoid going for the newer hard and fast cures as the meds for those tend to have some serious side effects...like liver/kidney damage, hair loss and others I don't recall off hand but when I was presented the choice I remember thinking I'd rather deal with the psoriasis than the major common side effects of the meds.