Introduction: Patients who have an adverse drug reaction are frequently labelled drug allergic without undergoing proper evaluation and confirmatory testing. These drug allergy labels may be inaccurate, leading to unnecessary lifelong avoidance. The aim of this study was to review the patients that underwent drug provocation tests (DPTs) in our centre and examine the usefulness of DPTs in confirming or rejecting a diagnosis of drug hypersensitivity. Materials and

Methods:

The study design was a retrospective chart review of all adult patients who underwent drug provocation in the allergy unit at the National University Hospital, Singapore, for single or multiple suspected drug allergies from the period January 2009 to June 2011.

Results:

Eighty-seven patients underwent 123 DPTs (median age 41; interquartile range 28 to 50). Twenty-one patients underwent multiple DPTs. The most common culprit drugs reported were antibiotics (43.9%) of which beta-lactams were implicated in 75.9% of the cases. This was followed by non-steroidal anti-inflammatory drugs (NSAIDS) in 15.4%, paracetamol in 7.3% and both NSAIDs and paracetamol in 3.3%. Rash was the most commonly reported symptom (41.5%), followed by angioedema (32.5%), anaphylaxis (9.8%), and other symptoms including respiratory (2.4%), gastrointestinal (0.8%) and others (13.0%). The majority of DPTs were performed to antibiotics (43.9%), NSAIDs (19.5%) and paracetamol (6.5%). DPTs were negative in 93.5% of subjects and positive in 6.5%. Of the 8 positive DPTs, none had a serious reaction, with 5 patients requiring rescue therapy, which comprised solely of oral antihistamines.

Conclusion:

Suspected drug hypersensitivity is common but true drug allergy is rare. DPTs remain the gold standard and should be included as part of an investigative protocol. DPTs are a safe and valuable diagnostic tool in the hands of the experienced clinician.

Red ants sting anaphylaxis was rarely reported from India. But angioedema due to ingestion of fried flying red fire ants in children is almost never reported from India and also very rarely reported from outside India. We report a case of recurrent non allergic angioedema following ingestion of fried flying red ants.

Various hypersensitivity reactions have been reported with aspirin and nonsteroidal anti-inflammatory drugs. Hypersensitivity can occur regardless of a chemical drug structure or its therapeutic potency. Allergic conditions include aspirin-exacerbated respiratory disease (AERD or aspirin-induced asthma), aspirin-induced urticaria/angioedema (AIU), and anaphylaxis. Several genetic studies on aspirin hypersensitivity have been performed to discover the genetic predisposition to aspirin hypersensitivity and to gain insight into the phenotypic diversity. This article updates data on the genetic mechanisms that govern AERD and AIU and summarizes recent findings on the molecular genetic mechanism of aspirin hypersensitivity.

BACKGROUND:

Although allergic reactions to insulin are uncommon, they can be difficult to diagnose and management may be very difficult in subjects with Type 1 diabetes with severe allergy. Access to allergists and specialist diagnostic tests is limited and few diabetes specialists are familiar with desensitization as a means of treating allergy. People with diabetes may develop symptoms which mimic insulin allergy but are attributable to other conditions. CASE REPORTS: Here we describe three cases of insulin allergy. One patient presented with severe, albeit localized, urticarial reactions at injection sites. The most severe case was a woman with recent-onset Type 1 diabetes who presented with grade 2 anaphylaxis. The third patient presented with generalized urticaria and angioedema. Insulin allergy was confirmed in all three cases.

METHODS:

Assessment involved measurement of immunoglobulin and anti-insulin antibody levels. Skin testing was performed in two cases. Treatments included desensitization in one case, alternative insulin preparations, antihistamines and continuous subcutaneous insulin infusion. In all three cases of insulin allergy there has been successful resolution of symptoms.

CONCLUSIONS:

The clinical assessment and investigation in cases of suspected insulin allergy is described, along with detailed algorithms for skin testing and desensitization. This case series demonstrates an approach to challenging cases of suspected insulin allergy which will be helpful for diabetes specialists.

Despite a thorough history and comprehensive testing, many children who present with recurrent symptoms consistent with allergic reactions elude diagnosis. Recent research has identified a novel cause for "idiopathic" allergic reactions; immunoglobulin E (IgE) antibody specific for the carbohydrate galactose-α-1,3-galactose (α-Gal) has been associated with delayed urticaria and anaphylaxis that occurs 3 to 6 hours after eating beef, pork, or lamb. We sought to determine whether IgE antibody to α-Gal was present in sera of pediatric patients who reported idiopathic anaphylaxis or urticaria.Patients aged 4 to 17 were enrolled in an institutional review board-approved protocol at the University of Virginia and private practice allergy offices in Lynchburg, VA. Sera was obtained and analyzed by ImmunoCAP for total IgE and specific IgE to α-Gal, beef, pork, cat epithelium and dander, Fel d 1, dog dander, and milk.Forty-five pediatric patients were identified who had both clinical histories supporting delayed anaphylaxis or urticaria to mammalian meat and IgE antibody specific for α-Gal. In addition, most of these cases had a history of tick bites within the past year, which itched and persisted.A novel form of anaphylaxis and urticaria that occurs 3 to 6 hours after eating mammalian meat is not uncommon among children in our area. Identification of these cases may not be straightforward and diagnosis is best confirmed by specific testing, which should certainly be considered for children living in the area where the Lone Star tick is common.

This is a case report involving a patient who was treated with topical 5-FU cream and subsequently developed a severe case of angioedema. This case presents the possibility of anaphylaxis to topical 5-FU treatments and/or the interaction with angiotensin converting enzyme inhibitors. To our knowledge there has been no prior reported case of this reaction. We present this unusual case along with a review of the current literature on angioedema.

Background:

The population of large parts of Africa, South America and travellers to these areas are at risk of yellow fever (YF) with a 50% mortality risk. Yellow fever vaccine (YFV) propagated in hens' eggs confers protection in 95% of the vaccinated. The rate of anaphylaxis for YFV ranges from 0.42 to 1.8/100,000 doses with most cases considered to be due to egg allergy. Egg allergy is a contraindication for the YFV. Nevertheless, the potential fatal sequelae from YF give the incentive to protect everyone at risk irrespective of their allergic status.

Methods:

Six subjects who had had a recent reaction to egg and who were travelling to endemic areas (3 adults and 3 children) underwent skin prick tests (SPT) with undiluted YFV and egg extract. Intradermal tests for YFV were undertaken at a 1:10 dilution. In 4 egg-allergic patients with a positive SPT to YFV, a 7-step desensitization protocol was used. A 2-step (10 + 90%) protocol was used in the 2 subjects with a negative YFV SPT. Premedication was not administered.

Results:

All 6 patients were successfully vaccinated. Four patients completed desensitization: 1 developed mild local erythema at the injection site, 1 had fleeting generalized urticaria with local erythema/angioedema and 2 did not experience any adverse reactions. Patients who received YFV in 2 steps developed no adverse reactions.

Conclusions:

We describe the successful administration of YFV in 6 egg-allergic patients. The Cambridge Allergy 7-step protocol allows for its safe administration in patients with positive SPT to YFV. A 2-step protocol can be used in patients with negative YFV SPT.

Hereditary angioedema (HAE) is a rare disorder associated with episodic attacks of well-demarcated angioedema. Attacks that affect the larynx can result in life-threatening airway obstruction.To examine efficacy and safety of ecallantide treatment for laryngeal HAE attacks.Data were combined from 4 clinical studies (EDEMA2, EDEMA3, EDEMA4, and DX-88/19) evaluating 30 mg of subcutaneous ecallantide for treatment of acute HAE attacks. Efficacy was assessed using 2 validated, HAE-specific, patient-reported outcome measures. The change in Mean Symptom Complex Severity (MSCS) score indicates change in symptom severity; a negative score indicates improvement. The calculated minimally important difference (MID) for change in severity is -0.30. The Treatment Outcome Score (TOS) measures treatment response. A positive score indicates improvement; the calculated MID is 30.Overall, 98 patients received ecallantide for 220 laryngeal attacks. The mean ± SD change in MSCS score was -1.1 ± 0.73 and -1.6 ± 0.68 at 4 and 24 hours, respectively. The mean ± SD TOS was 73.5 ± 35.8 and 85.5 ± 27.8 at 4 and 24 hours, respectively. Median time to significant improvement was 185 minutes (95% confidence interval, 167-226). One attack required intubation. Four treatment-emergent serious adverse events were reported, including 2 HAE attacks that resulted in hospitalization and 2 anaphylactic reactions. One of these reactions required treatment with epinephrine, but both patients recovered fully. There were no deaths.In this large attack series, ecallantide was effective for treatment of laryngeal HAE attacks. There is a risk of hypersensitivity, including anaphylaxis, consistent with product labeling. As such, ecallantide should be administered under the supervision of a health care professional.clinicaltrials.gov Identifiers: not applicable for EDEMA2 (trial was conducted before implementation of registration requirements); NCT00262080 for EDEMA3, NCT00457015 for EDEMA4, and NCT00456508 for DX-88/19.

The weaver ants (Oecophyllas maragdina), the tropical ants commonly found in Asia and Australia, can produce eggs which become the expensive delicacies for Thai people especially in the northern and northeastern part of Thailand. Anaphylactic reaction can occur from the most common triggers of ingested foods and drugs. Some hidden and newly recognized foods are now described as the triggers of anaphylaxis. This is the case report of anaphylaxis to the weaver ant eggs of after ingesting them for 2 hours and produced anaphylactic reactions, including generalized urticaria, angioedema, wheezing and gastrointestinal symptoms. The diagnostic test was performed to confirm IgE-mediated reaction with skin prick test for the fresh weaver ant egg's extract and the result was positive. To date, there is also no information about the exact major allergens of these weaver ant eggs and might need to be further explored.