Allergy symptoms such as hives, rash, swelling and fever can occur in response to medications. In most cases, a reaction to a medication is not mediated by the immune system but is instead an undesired side effect of the medication. However, an insulin allergy occurs when the immune system reacts inappropriately when exposed to injected insulin. This is a rare allergy that may occur in diabetic patients who are on insulin replacement products. It can be a serious issue because patients who are diabetic often need insulin to survive.
Skin Reactions
According to an article published in the June 2008 issue of the "European Journal of Allergy and Clinical Immunology," skin reactions are a common manifestation of an allergic reaction to insulin. Rash, hives or swelling of the face and hands may occur. Hives are small raised bumps that are extremely itchy in nature. A localized reaction at the site of the injection involving excessive swelling and pain can also occur. These skin reactions occur within an hour of administration of the medication. Diphenhydramine, an antihistamine used for allergies, may be needed to relieve the itching from the rash or hives. Ice may help to relieve the swelling for a localized skin reaction.
Shortness of Breath
Shortness of breath, cough or other respiratory symptoms are symptoms of a systemic allergic reaction to insulin. These symptoms occur within an hour of administration of insulin in allergic patients, and may require an antihistamine as well as epinephrine to reverse the reaction. If a patient with an insulin allergy develops shortness of breath, he should go to the emergency department immediately. Shortness of breath associated with an allergic reaction can quickly become life-threatening.
Lightheadedness
Lightheadedness, dizziness or syncope -- partial or complete loss of consciousness -- are other common manifestations of an allergy to insulin. Like shortness of breath, these are serious and potentially life-threatening symptoms that require emergency medical treatment. When a patient these systemic symptoms in response to an insulin allergy, testing can be performed to determine whether a different type of insulin could be given safely. A procedure called desensitization can be used if all types of insulin cause a reaction. Desensitization is the process of giving very small amounts of medication and increasing the dose gradually until the body no longer responds so dramatically to the allergen. Once the desensitization has taken place, the patient must take insulin daily to keep from developing another allergy to the medication.
