Dr. Justine A. Lee, DVM, DACVECC, "
A Quick Guide to Allergic Reactions in Dogs," (n.d.?),
Pet Health Network.
Lists "life threatening reactions" requiring "immediate visit" to ER
*Collapse
*Difficulty breathing due to inflammation or swelling of the throat/airway
*Shock (e.g., an elevated heart rate, low blood pressure)
*Abnormal heart rhythm
Corticosteroids are among the common treatments for allergic reactions.
Article says, "With mild allergic reactions, you can consult your veterinarian about just treating with Benadryl at home (make sure the Benadryl doesn’t have any added other ingredients). The dose of Benadryl is typically 1 mg per pound of weight of your dog (so a 50 pound dog would get 50 mgs of Benadryl)."