How to tell if i recently acquired an allergic reaction?

Symptoms: An allergic reaction can present with various features. These include itching, swelling, sneezing, coughing, wheezing, vomiting, diarrhea, nasal congestion, hives. These symptoms could occur after taking a medication, being around a pet, during a particular season of the year, etc. Timing and above symptoms will make one suspicious. An allergist can confirm if an allergy is present.