Mammalian meat allergy emerges after tick bite: the alpha-gal syndrome

Alpha-gal syndrome (AGS) is a hypersensitivity reaction to mammalian meat that develops after tick bite exposure. AGS was first described in 2009 and testing for the allergy has become available in the last decade. We report the case of a 56-year-old farmer with a history of frequent lone star tick bites who presented with a 7-year history of diffuse urticaria occurring hours after eating red meat. AGS is likely underdiagnosed because of the unusual presentation of the allergy, historic lack of available testing, and deficiency of physician knowledge about the condition. Recognition of AGS is important both to help alleviate symptom burden and to avoid iatrogenesis. Patients with AGS should not receive products containing mammalian products, such as cat-gut suture, porcine-derived heart valves, and bovine-derived vaccines. Patients with AGS may present in a variety of clinical environments and physicians of all kinds should be able to recognise the symptoms.

A Case of α-Gal-Unrelated Red Meat-Induced Urticaria Treated by Omalizumab

A 70-year-old healthy woman was referred to our hospital for chronic urticaria. She did not have a history of allergy, asthma, and rhinitis. She was initially diagnosed with α-gal-related urticaria based on an episode of delayed-type urticaria after eating red meat. The results of the intracutaneous allergen test for beef and pork were negative. Fluorenzyme immunoassays specific for IgE against α-gal, beef, and pork were also negative. She was diagnosed with an α-gal-unrelated red meat allergy following the reproduction of urticaria by a food challenge test. The patient was unresponsive to several drugs, including antihistamines or immunosuppressants. However, omalizumab administration suppressed her symptoms. <b><i>Key Clinical Message:</i></b> The diagnosis of red meat allergy may require a repeatability test by consuming red meat even though serum α-gal IgE antibody might be negative. The α-gal-unrelated red meat urticaria may be responsive to omalizumab.

Red meat causing delayed anaphylactic airway edema: a case report

<p class="abstract">The goals of emergency management of angioedema include prevention of spontaneous eruption, maintaining and securing the airway and to stop the progression of the disease. Laryngeal edema is one of the life-threatening complications of angioedema that can be managed by endotracheal intubation or emergency tracheostomy or cricothyrotomy. Recently, delayed onset food induced anaphylactic reactions are being recognised widely due to better clinical knowledge and technology that can substantiate the diagnosis. The classical finding of anaphylaxis to only proteins have been disproved and delayed onset food allergy (i.e.) 3-6 hours after ingestion of food has been attributed to specific carbohydrate moieties in glycolipids and glycoproteins such as Galactose-α-1,3-galactose found in red meat (beef, pork and lamb). Even though it is seen rarely in the Indian population, it should be a part of the diagnostic algorithm in order to prevent fatal complications. Hereby reporting 39 years old male with undiagnosed red meat allergy presented with features of foreign body sensation throat and laryngeal oedema and managed conservatively with steroids and nebulisation.</p>

The first reported cases of meat allergy following tick bites in the UK

Allergic reactions frequently involve the production of immunoglobulin E (IgE) antibodies to proteins. However, reactions directed against carbohydrate moieties are increasingly being recognised. Tick bites can contribute to the development of immunoglobulin E to the galactose-1,3-galactose (alpha-gal) moiety on tick salivary proteins. These IgE molecules can cross-react with alpha-gal found in red meats, causing Type I IgE-mediated hypersensitivity reactions to these foods. We present three cases of delayed reactions to beef, pork and lamb in patients with prior tick bites and in the presence of a positive-specific IgE to alpha-gal. Patients were advised to avoid red meat consumption and to carry emergency treatment in the form of anti-histamines with or without adrenaline autoinjector devices. This is the first published report of red meat allergy caused by tick bites suffered in the UK.