What I'm looking for is a simple phrase in plain english for your average reader that mentions/implies skin. How about:
an eruptive viral skin infection (which I'm leaning towards)
Hello. I am not sure what you mean by "simple". An "eruptive viral skin infection" does not seem that simple to me, but then again, I am not sure what you mean by average reader. An average reader of what? A newspaper? A book? A journal?
Where does the "viral" come from (if you only want "something simple" implying skin)? Why not creeping eruption
(caused by hookworms -larvae-
by the way) or any other bacterial skin infection
? A rash (btw) does not an infection constitute.
Be it an erythema or an exanthema (inflammatory response, yes, but invasion by pathogens, different story. For example (see) contact dermatitis
My point is, better to give the sentence in Greek.
You see, "skin plague" does not really say anything to me, certainly not in relation to "εξανθηματική νόσος" (even in hist. context) and we can go on and on, debating terminology -
(φλυκταινίτσες all around) - in a somewhat pointless manner.