INTRODUCTIONPatients 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 METHODSThe 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.

RESULTSEighty-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.

CONCLUSIONSuspected 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.

Adult ; Anti-Bacterial Agents ; adverse effects ; Drug Hypersensitivity ; diagnosis ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Reproducibility of Results ; Retrospective Studies ; Singapore ; Skin Tests ; methods

Food allergy is defined as reaction to a food which has an immunologic mechanism. Its prevalence is increasing in children globally and is therefore of increasing clinical importance. A useful clinical approach is to distinguish food allergic reactions by the timing of clinical reaction in relation to food exposure and classified as immediate (generally IgE-mediated) and delayed (generally non-IgE-mediated), with the exception of eczema and eosinophilic gastrointestinal disease, which, when associated with food allergy may be associated with either mechanism. This review is aimed at providing the clinician with a Singaporean perspective on the clinical approach and management of these disorders.
Breast Feeding ; Child ; Child, Preschool ; Eczema ; diagnosis ; immunology ; Food Hypersensitivity ; diagnosis ; prevention & control ; Humans ; Hypersensitivity, Delayed ; diagnosis ; prevention & control ; Immunoglobulin E ; blood ; Infant ; Infant, Newborn ; Skin Test End-Point Titration

INTRODUCTIONFood-dependent exercise-induced anaphylaxis (FDEIA) is an uncommon and under-recognised syndrome that clinicians may not consider in a patient presenting with anaphylaxis.

CLINICAL PICTUREWe describe here 5 patients aged 9 to 20 years old who presented at a local tertiary hospital over a 2-year period from August 2006 to July 2008. All presented with urticaria, 4 were hypotensive, 2 had angioedema and another 2 had dyspnoea. The symptoms occurred between 15 and 150 minutes (mean, 81) after exercising and consuming various food. All had consumed shellfish. All patients were admitted with the diagnosis of anaphylaxis of undefined aetiology. Diagnosis of FDEIA was only reached upon referral to an allergist.

TREATMENT AND OUTCOMEPatients were treated with standard medicines for anaphylaxis including adrenaline, antihistamines, steroids and fluid flushes. Symptoms resolved in 2 to 3 days with no further episodes. At discharge, patients were prescribed epinephrine auto-injectors and given written anaphylaxis management plans.

CONCLUSIONSMore public awareness and strategies to ensure accurate diagnosis and management of this condition are necessary.

Adolescent ; Anaphylaxis ; drug therapy ; etiology ; Angioedema ; etiology ; Animals ; Bronchodilator Agents ; therapeutic use ; Child ; Dyspnea ; etiology ; Epinephrine ; therapeutic use ; Exercise ; Female ; Food Hypersensitivity ; diagnosis ; drug therapy ; etiology ; Humans ; Male ; Retrospective Studies ; Seafood ; adverse effects ; toxicity ; Syndrome ; Urticaria ; etiology ; Vasoconstrictor Agents ; therapeutic use ; Young Adult