Doctors often prescribe a medication called Zithromax to patients who are suffering from a variety of different bacterial infections. This includes skin infections, respiratory infections, ear infections or sexually transmitted diseases. You may suffer an allergic reaction after taking the drug, which may return even after you stop taking Zithromax. Therefore, talk to your doctor immediately if you suffer signs of a severe allergic reaction such as difficulty breathing, dizziness, swelling of the throat, face or tongue or a rash.