Some of the symptoms of an allergic reaction to Neosporin include itchy skin, a rash or swelling of the skin, according to WebMD. During a severe reaction, the person may feel dizzy, have difficulty breathing, or experience facial or throat swelling.
Neosporin can cause contact dermatitis for people who are allergic to one or more ingredients. The condition presents with a rash around the application area, red skin, dry or scaly patches of skin, and oozing blisters. The allergic reaction can also cause a strong burning sensation or cause hives at the area of application or in other spots on the body, according to Cleveland Clinic.