1.M.C., a 23-year-old woman, has developed a skin rash as well as nausea and vomiting, after taking an antimicrobial drug for a short time. The skin rash is red and quite itchy and is spreading over...

1.M.C., a 23-year-old woman, has developed a skin rash as well as nausea and vomiting, after taking an antimicrobial drug for a short time. The skin rash is red and quite itchy and is spreading over her entire body. The physician stops the medication because of this allergic reaction. The patient has a history of skin rashes, both eczema and contact dermatitis, since infancy. She has had hay fever during the summer and fall for the past few years.

(1)Why would the physician consider this an allergic reaction to a drug?

(2)What kind of hypersensitivity is hay fever, and what are the signs of it?