<s>[INST] How do we determine if this is a case of shingles or a case of contact dermatitis. Full body rash, some open, some scabs, ER docs unable to help, PCP has been unavailable for review. Was looking at photos and it sure looks like shingles has attacked my husband! But it also looks like a dermatitis problem a friends has had for four years that has yet to be diagnosed! Rash is accompanied by severe edema especially on legs and arms. He tells me he is not voiding the amount of water he is drinking and the edema is quite pronounced. I have been out of town since this started last Wednesday and it is now Tuesday night. Where do we start tomorrow? [/INST] Hello, This does not sound at all like shingles. Shingles is usually only on one side of the body and in a nerve root distribution. The most common is on the flank, but it can occur in other places. Full body rash is not common and usually only occurs in people that have immune deficiencies. The edema is concerning and may mean something severe is going on with the heart or kidneys. He needs to see a doctor as soon as possible for blood tests and an exam. If this means returning to Emergency then you need to do that. Regards </s>