Category: For Healthcare Professionals

Information for healthcare professionals

FDA Warns of Severe Rebound Itching After Stopping Cetirizine (Zyrtec) or Levocetirizine (Xyzal): What You Need to Know

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🛑 New FDA Safety Alert: Antihistamine Withdrawal Can Trigger Severe Itching In May 2025, the U.S. Food and Drug Administration (FDA) issued a new safety warning about rebound itching after stopping cetirizine (Zyrtec) or levocetirizine (Xyzal)—two of the most commonly used antihistamines. This severe itching reaction, often mistaken for allergy relapse, may occur especially in people who have taken the drug daily for several months. 🔎 Key Findings from the FDA Investigation Between April 2017 and July 2023, the FDA identified 209 confirmed cases globally—197 in the U.S.—involving moderate to…

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Sebetralstat: The First Oral Treatment for HAE Approved by FDA

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sebetralstat

Oral HAE treatment is now FDA-approved. On July 7, 2025, Sebetralstat (Ekterly®) became the first oral on-demand therapy for acute attacks in hereditary angioedema (HAE), marking a major shift in how this rare condition is managed. Hereditary Angioedema (HAE) is a rare genetic disorder that causes unpredictable, recurrent episodes of swelling, often affecting the face, throat, gastrointestinal tract, and extremities. If untreated, these attacks can be life-threatening. Until recently, on-demand treatment for HAE required injections only. While berotralstat (Orladeyo®) became the first oral medication approved for prophylaxis in 2020, acute…

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The Basophil Activation Test (BAT): A Game-Changing Tool for Food Allergy Diagnosis

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Basophil Activation Test (BAT) in Food Allergy

Diagnosing food allergies accurately remains one of the biggest challenges in allergy medicine. Traditional approaches like skin prick tests (SPT) and specific IgE blood tests can tell us if someone is sensitized to a food, but they don’t always predict whether that person will actually have an allergic reaction. Meanwhile, oral food challenges (OFCs)—the gold standard—are time-consuming, expensive, and carry real risks of severe reactions. Enter the Basophil Activation Test (BAT): a revolutionary diagnostic tool that’s changing how we approach food allergy diagnosis. 🧪 What Makes BAT Different? BAT is…

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Beyond the Surface: Rethinking Rechallenge in Suspected Drug-Induced SSLR and Serum Sickness

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Serum sickness or SSLR

IntroductionDrug-induced serum sickness-like reactions (SSLR) are a complex and often confusing condition for both patients and healthcare providers. These reactions, usually triggered by medications like beta-lactam antibiotics, can cause rash, fever, and joint pain. While SSLRs are generally thought to be milder than true serum sickness, which is caused by immune complexes circulating in the blood, the two conditions can look very similar. The real challenge? In most cases, we rely on patient history alone to make the distinction, and that can be dangerously misleading. The Diagnostic Dilemma: SSLR vs.…

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When and How to Perform Drug Provocation Tests in Drug Hypersensitivity: Timing Matters

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Introduction Drug provocation test timing plays a critical role in evaluating suspected drug allergies. Drug provocation testing (DPT), also known as a drug challenge, remains the gold standard for confirming or ruling out drug hypersensitivity. However, success depends heavily on understanding how soon after drug exposure symptoms appear. By tailoring the timing and protocol of DPT based on the type of reaction—immediate, delayed, or severe—clinicians can improve diagnostic accuracy and minimize risk. This post outlines practical strategies, guideline updates, and real-world challenges that affect how and when drug provocation tests…

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Rethinking Drug Allergy Management: Finding Balance Between Caution and Access in SCARs

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Drug allergies present a complex landscape, demanding tailored management strategies based on the reaction’s nature and severity. We’ve witnessed significant progress in “de-labeling” allergies to common drugs like penicillin through careful testing, allowing many to safely access essential treatments. However, the approach to severe cutaneous adverse reactions (SCARs) – encompassing Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), and Acute Generalized Exanthematous Pustulosis (AGEP) – often stands in stark contrast: a broad and often indefinite avoidance of all potentially implicated drugs. While the…

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Seafood Allergy: Causes, Symptoms, Diagnosis, and Prevention

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Seafood allergies are a serious and potentially life-threatening condition affecting millions worldwide. Whether you’re allergic to fish, shellfish, or both, understanding the causes, symptoms, and prevention strategies is crucial for managing your allergy safely. This comprehensive guide will cover everything you need to know about seafood allergies, including diagnosis, myths, and emergency preparedness. What Causes Seafood Allergies? Seafood allergies occur when the immune system mistakenly identifies certain proteins in fish or shellfish as harmful, triggering an allergic reaction. The primary allergens are: Fish vs. Shellfish Allergies: What’s the Difference? Symptoms…

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Mastering Angioedema Diagnosis: Recognizing Mimics and Uncommon Causes

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Spotting Angioedema: Unmasking the Unusual Culprits!

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Chemotherapy Hypersensitivity Reactions: Immediate vs. Non-Immediate Responses and How to Manage Them

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Introduction Hypersensitivity reactions to chemotherapy—ranging from mild rashes to life-threatening anaphylaxis—can complicate treatment and require expert diagnosis and management. Immediate Reactions: Diagnosis and ManagementImmediate hypersensitivity reactions to chemotherapies are relatively common and easier to confirm compared to non-immediate reactions. Symptoms such as urticaria, wheezing, or anaphylaxis often appear during or shortly after drug administration. In some cases, nausea, vomiting, or back pain may also occur as part of anaphylaxis symptoms, though these are less typical and can overlap with side effects of chemotherapy itself. Key Diagnostic Tools:• Skin Testing with…

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Reevaluating the Approach to Severe Cutaneous Adverse Reactions (SCARs): Is Drug Rechallenge Always Off the Table?

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Severe Cutaneous Adverse Reactions (SCARs), such as acute generalized exanthematous pustulosis (AGEP), Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), and Stevens-Johnson Syndrome (SJS), are among the most feared drug-related complications. These conditions can result in devastating outcomes, and the conventional approach to managing SCARs emphasizes strict avoidance of the suspected culprit drug to prevent potentially fatal recurrences. But is avoidance always the only path forward? Could there be room for a more nuanced strategy in specific cases? Not All SCARs Are Created Equal SCARs represent a spectrum of disorders,…

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