Aspirin Allergy: Mechanisms, Reactions, and Management
Aspirin allergy is often misunderstood, as it encompasses a range of reactions rather than a single immunological response. Aspirin functions by inhibiting the cyclooxygenase-1 (COX-1) enzyme, and other nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, share this mechanism, which can result in overlapping adverse effects in sensitive individuals. However, some NSAIDs, including celecoxib and meloxicam, are more selective for COX-2 inhibition and are associated with fewer allergic reactions. Celecoxib, despite its lower risk, contains a sulfur component, which may pose additional concerns for individuals with sulfa allergies. Ketorolac (Toradol), another NSAID, inhibits both COX-1 and COX-2 equally and is recognized as a potent analgesic.
Reactions to aspirin are highly variable and not always mediated by immunoglobulin E (IgE). Some patients experience respiratory symptoms, such as those seen in aspirin-exacerbated respiratory disease (AERD). This condition involves asthma and rhinosinusitis with nasal polyps, where aspirin-induced COX-1 inhibition disrupts the arachidonic acid pathway, leading to an overproduction of leukotrienes and subsequent airway inflammation. Others may develop angioedema or swelling of the tongue and throat. This reaction, which is distinct from classic anaphylaxis, is thought to be mediated by bradykinin rather than IgE. In rare cases, aspirin can cause true IgE-mediated allergic reactions, presenting with symptoms such as urticaria, hypotension, or anaphylaxis.
For patients requiring aspirin for medical conditions, such as cardiovascular disease, despite a history of hypersensitivity, desensitization is an effective option. This process involves administering gradually increasing doses of aspirin, starting as low as 1/100th of the therapeutic dose, under strict medical supervision. While desensitization is often effective for IgE-mediated hypersensitivity and certain other reactions, it is not appropriate for all types of aspirin-related adverse effects.
Aspirin’s ability to shift bradykinin levels and alter chemical mediators underlies its potential to induce diverse reactions, many of which do not align with traditional allergic mechanisms. Accurate diagnosis and differentiation between IgE-mediated and non-IgE-mediated reactions are essential for effective management. Dr. Arthur Lubitz tailors the use of selective NSAIDs, desensitization protocols, or alternative therapies to each patient’s clinical needs to minimize risks while addressing therapeutic requirements. Understanding the mechanisms behind aspirin-related reactions is critical for optimizing treatment and ensuring patient safety.
If you need to book an appointment for your allergies or asthma, you can book your appointment online, or call (212) 247-7447.