Subcutaneous immunotherapy uses a series of injections as a way of dispensing the required medication. Although sublingual immunotherapy medications can be taken anywhere, subcutaneous immunotherapy, also known as allergy shots, must be given in a medically supervised environment. Allergy shots are given according to a specific schedule. The shots are given once a week for several weeks with the dosage increasing with each injection. When the first maintenance dosage is reached, the shots are given every two weeks, again with the dosage increasing with each injection.
Subcutaneous immunotherapy may also produce the same side effects as the sublingual form. With injections, the site of the shot may become red, irritated, and itch slightly. The side effects of the injections only last for a few hours. If the side effects last longer than normal, they should be reported to the physician so the dosage can be adjusted for future injections. In most cases, the doctor or nurse who give the injection will request the patient wait in the office for at least 20 to 30 minutes to ensure there is not a reaction.