Symptoms of Type 1 Hypersensitivity Reactions

Type 1 hypersensitivity reactions, also known as immediate hypersensitivity, are mediated by immunoglobulin E (IgE) antibodies. Common symptoms of these reactions include asthma, rhinitis, and atopic diseases such as eczema. Late phase reactions can occur 2-8 hours after contact with the antigen and last 2-3 days. Some patients may experience frank arthritis, edema, or gastrointestinal symptoms. Symptoms of type 1 hypersensitivity reactions can be self-limited and typically last 1-2 weeks.

Drugs that can Induce a Type 1 Hypersensitivity Reaction

Some drugs can induce type 1 hypersensitivity reactions. These include opiates, vancomycin (Vancocin), and NSAIDs (including COX-2 inhibitors), methicillin, antimicrobials, and cimetidine. Type 1 hypersensitivity reactions can lead to anaphylaxis, allergic asthma, urticaria, angioedema, allergic rhinoconjunctivitis, and some types of drug reactions known as serum sickness. It is important to note that the same drug may cause different reactions in different individuals, so it is important to be aware of the potential for a type 1 hypersensitivity reaction when taking any medication.

Diagnosis and Treatment of Type 1 Hypersensitivity Reactions

Type 1 Hypersensitivity reactions are IgE mediated hypersensitivity reactions that can be triggered by various allergenic agents, such as food, drugs, and environmental allergens. The symptoms of type 1 hypersensitivity reactions usually manifest within minutes after contact with the antigen and can range from mild to life-threatening. To diagnose type 1 hypersensitivity reactions, a doctor may assess the person's history and physical symptoms, as well as conducting skin prick tests or blood tests to detect IgE antibodies. Treatment of a type 1 hypersensitivity reaction is aimed at reducing the body's allergic response and may include medications such as epinephrine, antihistamines, and corticosteroids. Avoidance of the allergen is often the first step in treating a type 1 hypersensitivity reaction.

Causes of Type 2 Hypersensitivity Reactions

Type 1 hypersensitivity reactions are caused by the binding of an antigen or allergen to mast cell-associated IgE. After detecting an antigen, the mast cells degranulate and release vasoactive amines, resulting in a range of clinical manifestations from urticaria to anaphylactic shock. In contrast, type 2 hypersensitivity reactions are caused by antibodies binding to antigens on the surface of cells. These reactions can be caused by antibiotics, drugs with pseudoallergic properties, or radiocontrast media and can result in cytotoxic effects such as hemolysis. In the next section, we will discuss the effects of antibiotics on type 1 hypersensitivity reactions.

Effects of Antibiotics on Type 1 Hypersensitivity Reactions

It is important to note that some antibiotics can interfere with the early phase of type 1 hypersensitivity reactions, leading to an increased risk of an allergic reaction. Penicillins and cephalosporins, two of the most commonly prescribed β-lactam antibiotics, are known to induce severe, life-threatening type I hypersensitivity reactions. In addition, other antibiotics such as sulfonamides and vancomycin (Vancocin) can cause pseudoallergic reactions that involve direct mast cell activation and degranulation. To reduce the risk of a type 1 hypersensitivity reaction, it is important to be aware of which drugs are more likely to cause an allergic reaction and to take steps to prevent or treat any symptoms that may occur.

Intramuscular Epinephrine Injection for Treatment of Type 1 Hypersensitivity Reactions

Epinephrine is the most commonly used, first-line medication for the treatment of Type I hypersensitivity reactions. It is a hormone that helps to reduce the severity of the reaction and can reverse the symptoms of anaphylaxis. Epinephrine should be administered as soon as possible following exposure to the allergen, preferably with an autoinjector or 1:1,000 solution. In cases of severe hypotension, a 1:10,000 w/v solution may also be necessary. It is important to recognize and act quickly when experiencing an allergic reaction, as it can have a wide range of clinical manifestations. The National Childhood Vaccine Injury Act of 1986 requires that vaccine manufacturers include information about the possibility of allergic reactions and provide Vaccine Emergency Use Authorization (EUA) if necessary. Furthermore, it is important to be aware of any drug interactions that may occur when taking certain medications as they can interfere with the effectiveness of epinephrine and other medications used to treat Type I hypersensitivity reactions.

Prevention of Type 1 Hypersensitivity Reactions

Prevention of type 1 hypersensitivity reactions is important, especially in children, as an estimated 8% of US children are affected.1 To help avoid reactions, schools can develop plans to prevent allergic reactions and provide epinephrine auto-injectors in case a reaction occurs. In addition to avoidance, premedication protocols using antihistamines, corticosteroids, and acetaminophen can be used to reduce the risk of a hypersensitivity reaction to biologicals. Intranasal application of antihistamines (e.g. AZE, olopatadine, and levocabastine) can also help deliver active drugs directly to the nasal mucosa and reduce the risk of a type 1 hypersensitivity reaction. The only treatment indicated to delay the onset of stage 3 type 1 diabetes is teplizumab (TZIELD). Finally, intramuscular epinephrine injection is the preferred treatment for anaphylaxis or other severe type 1 hypersensitivity reactions.

Immediate Reaction: Allergic Reaction within Minutes of Contact with the Antigen

When exposed to an allergen, an immediate reaction can occur within minutes. This is known as Type I hypersensitivity or immediate hypersensitivity, and is part of the Gell and Coombs classification of allergic reactions. It is mediated by IgE antibodies, which bind to the surface of mast cells and cause them to release histamine and other mediators of the allergic response. Such reactions can be caused by iodinated radiocontrast media (RCM), opiates, or vancomycin, and may appear similar clinically to urticaria. To counteract the allergic reaction, an antihistamine can be taken orally or topically, or inhaled. In cases of anaphylaxis, a severe allergic reaction which is an emergency, intramuscular epinephrine injection is used for treatment. To prevent such reactions in the future, avoidance of the offending agent is the first step in treatment.

Avoidance as the First Step in Treatment of Allergic Conditions

The immediate reaction to an allergen is an allergic reaction and avoidance of the allergen is the first step in treatment for allergic conditions. This includes avoiding contact with the allergen, as well as avoiding foods, drugs, or other substances that may contain it. Oral or topical H1 antihistamines and oral or inhaled corticosteroids can be used to reduce symptoms of an allergic reaction. Epinephrine is the drug of choice for anaphylaxis, which is a severe allergic reaction that can be life-threatening. Nasal corticosteroids can be used to reduce inflammation and swelling of the nasal passages to alleviate symptoms. Intramuscular epinephrine injections may also be necessary in cases of anaphylaxis. It is important to assess the risk factors that may increase the likelihood of a type 1 hypersensitivity reaction and take preventative measures to avoid them.

Conclusion

In conclusion, type 1 hypersensitivity reactions can be caused by a range of medications and environmental triggers. The mainstay of treatment for these reactions is avoidance of the offending agent and the use of H1 antihistamines and oral or inhaled corticosteroids. In more severe cases, epinephrine may be required. It is important to monitor for any signs or symptoms of a reaction. Early diagnosis and recognition of the signs and symptoms are important in providing effective treatment. While avoidance is the best treatment, it is not always possible. As such, knowledge of the medications that can induce a type 1 hypersensitivity reaction is key to preventing further episodes.