Doxycycline antibiotic allergy: does vomiting count or just rashes?

Yes. One of the most common symptoms for patients allergic to drugs is vomiting in gastric distress.

Related Questions

Antibiotic allergy or something else, if your rash comes 2 days after your last dose?

Delayed reaction. Some allergies may be of delayed onset. Also it's possible that another medication has combined with the first own to cause the symptoms. Last, sun exposure may cause skin changes while taking certain medications (photophobia).