Hi, Symptoms of an allergic reaction to amoxicillin, a member of penicillin, may include anaphylaxis, hives, below-the-skin swelling, or asthma symptoms. Hives caused by amoxicillin, which appear as red, raised patches of skin, cause intense itching, and when they occur in the throat or mouth, they can cause difficulty breathing and swallowing. Hives from amoxicillin are also referred to as urticaria and can erupt suddenly and present themselves in a variety of sizes and shapes. Usually appear on day 5-7 from the start of the Amoxicillin or Augmentin, but can occur at any time during the course of the medication. It always appears on the chest, abdomen, or back and usually involves the face, arms, and legs. These allergy symptoms of Augmentin typically arise in patients within a few minutes of treatment. Confusion or Anxiety Patients who are allergic to Augmentin can appear unusually confused or anxious after taking a dose of this medication, MedlinePlus warns. Augmentin contains a combination of amoxicillin and clavulanate potassium. Amoxicillin is an antibiotic belonging to a group of drugs called penicillins. Hi, I was taking augmentin for a supposed sinus infection, which later on it was determined it was not an infection at all, just congestion. On the seventh day of a ten day course I borke out in hives all over my body and by morning I had angiodema around my eyes. Augmentin is not expected to be harmful to an unborn baby, but a woman should tell her doctor if she is pregnant or plans to become pregnant during treatment. Amoxicillin and clavulanate potassium can pass into breast milk and may harm a nursing baby. If you develop a rash, hives or difficulty breathing after taking certain medications, you may have a drug allergy. Allergic Rhinitis If you sneeze a lot, if your nose is often runny or stuffy, or if your eyes, mouth or skin often feels itchy, you may have allergic rhinitis. Note: This document contains side effect information about amoxicillin / clavulanate. Some of the dosage forms listed on this page may not apply to the brand name Augmentin.