From the Guidelines
Approximately 1-2% of the population experiences true allergic reactions to Benadryl (diphenhydramine), with symptoms including hives, skin rash, itching, swelling, difficulty breathing, wheezing, dizziness, and in severe cases, anaphylaxis. These reactions occur because the immune system mistakenly identifies the medication as harmful and releases chemicals that cause allergy symptoms 1. It's essential to distinguish between true allergic reactions and common side effects of Benadryl, which include drowsiness, dry mouth, dizziness, and constipation.
Some key points to consider:
- Adverse drug reactions (ADRs) may affect up to one-tenth of the general population and up to 20% of all hospitalized patients, with more than 10% of all ADRs being drug hypersensitivity reactions (DHRs) 1.
- The incidence of anaphylaxis due to medication triggers, including Benadryl, is increasing over time 1.
- If you suspect you're allergic to Benadryl, seek immediate medical attention, especially if experiencing severe symptoms like difficulty breathing or swelling of the face or throat.
- Alternative antihistamines from different chemical classes may be recommended by your healthcare provider if you need antihistamine treatment but have a confirmed Benadryl allergy.
In terms of management, epinephrine administered intramuscularly is the first-line treatment for anaphylaxis, including anaphylaxis caused by Benadryl allergy 1. It's crucial to recognize the signs and symptoms of anaphylaxis promptly and administer epinephrine without delay.
Overall, while the exact percentage of the population allergic to Benadryl is not well-established, it's clear that true allergic reactions to this medication can occur and may be life-threatening. Therefore, it's essential to be aware of the symptoms and seek medical attention immediately if suspected.
From the Research
Allergic Reactions to Benadryl
- The provided studies do not directly report the percentage of the population allergic to Benadryl (diphenhydramine) 2, 3, 4, 5, 6.
- However, it is known that diphenhydramine is a first-generation antihistamine used to treat allergic reactions, and toxicity may occur with its use, especially in large doses or via the intravenous route 2.
- Symptoms of allergic reactions to diphenhydramine are not explicitly stated in the provided studies, but it can be inferred that they may include cardiac arrest, as reported in a case study of an infant who suffered cardiac arrest after administration of intravenous diphenhydramine 2.
- Other studies discuss the efficacy and safety of antihistamines, including diphenhydramine, in treating allergic rhinitis and other conditions, but do not provide information on the prevalence of allergies to Benadryl specifically 3, 4, 5, 6.
Prevalence of Allergies
- A study on the prevalence of peanut and tree nut allergy in the US found that 1.4% of the population reported an allergy to peanuts or tree nuts, but this is not directly related to Benadryl allergy 5.
- Another study found that 19.6% of children were atopic, meaning they had a positive reaction to one or more allergens, but this study did not specifically investigate Benadryl allergy 3.
Treatment of Allergic Reactions
- A retrospective study compared the treatment of allergic reactions in cats with diphenhydramine alone or in combination with a glucocorticoid, but did not provide information on the human population or Benadryl allergy specifically 6.
- The study found that there was no difference in the resolution of clinical signs between the two treatment groups, and that glucocorticoids may not be indicated for the treatment of acute allergic reactions 6.