Pediatric Drug Allergy Immunology and Allergy Clinics Approach to beta lactam allergy in critical care EMCrit Project Peptides and allergic reactions. , Dont get too comfortable taking gallons of peptides without any thought, Look Well. Feel Well. Be Well. Peptide injections can sometimes cause redness or itching at the injection site, but most of the time this is not a true allergy. In the skin, we have mast cells that contain histamine. These cells Drug Allergies UF Health