Are there any side effects for allergy shots?

Common side effects include redness, swelling, or itching at the injection site. These usually go away on their own and can be eased with ice packs. Some people may experience mild allergy symptoms like congestion or sneezing after shots, which can be treated with antihistamines.
Rarely, a severe allergic reaction called anaphylaxis can occur. This is why you’ll be monitored after each shot.