Venom allergy testing: is a graded approach necessary?

BACKGROUND: Many institutions recommend a stepwise approach to intradermal testing for venom allergy. This is costly and uncomfortable for the patient. The rationale for this approach is the risk of potential adverse reactions to testing with the maximal dose alone. OBJECTIVE: To evaluate the safety of a single-step approach to venom allergy testing. METHODS: The authors retrospectively reviewed the charts of 300 consecutive patients with suspected hymenoptera venom allergy based on history who underwent venom allergy testing in a single allergist's clinic where a single-step protocol had been adopted. All patients had positive skin test reaction to at least 1 hymenoptera venom. Charts were reviewed for testing protocol used, results of testing, and reported immediate and delayed adverse reactions to testing. RESULTS: All patients underwent testing with an identical single-step protocol with an intradermal dose of 0.02 mL of a 1.0-µg/mL concentration of each of the 5 commercially available vespid and bee venoms. Only 1 patient reported an adverse reaction to testing, which was delayed until the morning after his visit. There were no immediate adverse reactions. The patient who had the delayed reaction was successfully started on venom immunotherapy subsequent to his reaction. CONCLUSION: A single-step venom allergy intradermal testing protocol with a 1.0-µg/mL concentration of commercially available extracts is a safe option, which, if adopted into practice, could lead to more streamlined care for patients and cost savings for the medical system.

Skin prick testing with extensively heated milk or egg products helps predict the outcome of an oral food challenge: a retrospective analysis.

BACKGROUND: Cow's milk and hen's egg are the most frequently encountered food allergens in the pediatric population. Skin prick testing (SPT) with commercial extracts followed by an oral food challenge (OFC) are routinely performed in the diagnostic investigation of these children. Recent evidence suggests that milk-allergic and/or egg-allergic individuals can often tolerate extensively heated (EH) forms of these foods. This study evaluated the predictive value of a negative SPT with EH milk or egg in determining whether a child would tolerate an OFC to the EH food product. METHODS: Charts from a single allergy clinic were reviewed for any patient with a negative SPT to EH milk or egg, prepared in the form of a muffin. Data collected included age, sex, symptoms of food allergy, co-morbidities and the success of the OFC to the muffin. RESULTS: Fifty-eight patients had negative SPTs to the EH milk or egg in a muffin and underwent OFC to the appropriate EH food in the outpatient clinic. Fifty-five of these patients tolerated the OFC. The negative predictive value for the SPT with the EH food product was 94.8%. CONCLUSIONS: SPT with EH milk or egg products was predictive of a successful OFC to the same food. Larger prospective studies are required to substantiate these findings.

An introduction to immunology and immunopathology.

In basic terms, the immune system has two lines of defense: innate immunity and adaptive immunity. Innate immunity is the first immunological, non-specific (antigen-independent) mechanism for fighting against an intruding pathogen. It is a rapid immune response, occurring within minutes or hours after aggression, that has no immunologic memory. Adaptive immunity, on the other hand, is antigen-dependent and antigen-specific; it has the capacity for memory, which enables the host to mount a more rapid and efficient immune response upon subsequent exposure to the antigen. There is a great deal of synergy between the adaptive immune system and its innate counterpart, and defects in either system can provoke illness or disease, such as autoimmune diseases, immunodeficiency disorders and hypersensitivity reactions. This article provides a practical overview of innate and adaptive immunity, and describes how these host defense mechanisms are involved in both health and illness.

Omalizumab: Practical considerations regarding the risk of anaphylaxis.

Omalizumab has demonstrated efficacy among patients with moderate to severe persistent allergic asthma, whose symptoms are inadequately controlled with other controller agents. This therapy is generally well tolerated, but there are some safety considerations, the most important of which is the rare, but potentially life-threatening, occurrence of omalizumab-associated anaphylaxis.In Canada, data from the manufacturer of omalizumab indicate that the frequency of anaphylaxis attributed to Xolair in post-marketing use is approximately 0.2%. Other researchers, including the American Omalizumab Joint Task Force (OJTF), have suggested a lower overall frequency of 0.09%.This paper provides a summary of the epidemiologic research carried out to date and presents a concise, practical set of recommendations for the prevention, monitoring and management of omalizumab-associated anaphylaxis. Prevention tips include advice on patient education measures, concomitant medications and optimal administration. For the first three injections, the recommendation is to monitor in clinic for two hours after the omalizumab injection; for subsequent injections, the monitoring period should be 30 minutes or an appropriate time agreed upon by the individual patient and healthcare professional.In the event that a patient does experience omalizumab-associated anaphylaxis, the paper provides recommendations for handling the situation in-clinic and recommendations on how to counsel patients to recognize the potential signs and symptoms in the community and react appropriately.

Skin prick testing in patients using beta-blockers: a retrospective analysis.

RATIONALE: The use of beta-blockers is a relative contraindication in allergen skin testing yet there is a paucity of literature on adverse events in this circumstance. We examined a population of skin tested patients on beta-blockers to look for any adverse effects. METHODS: Charts from 2004-2008 in a single allergy clinic were reviewed for any patients taking a beta-blocker when skin tested. Data was examined for skin test reactivity, type of skin test, concomitant asthma diagnosis, allergens tested, and adverse events. RESULTS: One hundred and ninety-one patients were taking beta-blockers when skin testing occurred. Seventy-two patients had positive skin tests. No tests resulted in an adverse event. CONCLUSIONS: This data demonstrates the relative safety of administrating of skin prick tests to patients on beta-blocker treatment. Larger prospective studies are needed to substantiate the findings of this study.

An introduction to immunology and immunopathology.

Beyond structural and chemical barriers to pathogens, the immune system has two fundamental lines of defense: innate immunity and adaptive immunity. Innate immunity is the first immunological mechanism for fighting against an intruding pathogen. It is a rapid immune response, initiated within minutes or hours after aggression, that has no immunologic memory. Adaptive immunity, on the other hand, is antigen-dependent and antigen-specific; it has the capacity for memory, which enables the host to mount a more rapid and efficient immune response upon subsequent exposure to the antigen. There is a great deal of synergy between the adaptive immune system and its innate counterpart, and defects in either system can provoke illness or disease, such as inappropriate inflammation, autoimmune diseases, immunodeficiency disorders and hypersensitivity reactions. This article provides a practical overview of innate and adaptive immunity, and describes how these host defense mechanisms are involved in both heath and illness.

Allergen immunotherapy in pregnancy.

BACKGROUND: Allergic diseases such as asthma and allergic rhinitis constitute a significant burden of disease among women of childbearing age and those who are pregnant. Adequately managing these conditions is paramount in reducing negative fetal outcomes as well as maternal complications during pregnancy. However, the potential for harm to both the mother and fetus demands carefully balancing efficacy and safety of treatment. Allergen immunotherapy (AIT) has emerged as a relatively safe and efficacious mode of therapy in both children and adults. AIT has also been considered for use during pregnancy. METHODS: A review of the literature was conducted for data regarding the safety of initiation and continuation of AIT during pregnancy as well as the effect of AIT on the development of atopy in offspring. MEDLINE and the Cochrane Library were searched for clinical trials, randomized control trials, observational studies and journal articles in English using the terms "Pregnancy" and "Immunotherapy" from 1900 to present. This yielded 4 studies (totaling 422 pregnancies receiving AIT) investigating the continuation of AIT in pregnancy, 2 (totaling 31 pregnancies receiving AIT) evaluating AIT initiation during pregnancy and 5 observing the effect of AIT on atopy in offspring. RESULTS: No significant difference was found in the incidence of prematurity, hypertension (HTN)/proteinuria, congenital malformations or perinatal deaths between the women continued on AIT (both subcutaneous (SC) IT and sublingual (SL) IT to inhalant allergens as well as venom IT) during pregnancy and controls. Similarly, there was no significant difference in maternal or fetal complications between pregnant women initiated on AIT and controls. Among the few pregnant women (10/453 pregnancies) who experienced generalized reactions while receiving AIT, none were found to have fetal complications. Neither SCIT nor SLIT during pregnancy altered the risk of developing atopic disease in offspring. CONCLUSIONS: Based on these data, the continuation of AIT during pregnancy appears safe. Furthermore, the few data available suggest that the initiation of AIT during pregnancy might also be safe, however, more data is required for a definitive conclusion. Lastly, available studies do not show a convincing reduction in the development of atopy in offspring from the administration of AIT during pregnancy.

Patients on subcutaneous allergen immunotherapy are at risk of intramuscular injections.

BACKGROUND: Allergen-specific subcutaneous immunotherapy is an effective treatment for certain allergic disorders. Ideally, it should be administered into the subcutaneous space in the mid-posterolateral upper arm. Injections are commonly given using a standard allergy syringe with a needle length of 13 mm. Therefore, there is a risk of intramuscular administration if patients have a skin-to-muscle depth <13 mm, which may increase the risk of anaphylaxis. The objective of this study was to determine whether the needle length of a standard allergy syringe is appropriate for patients receiving subcutaneous immunotherapy. METHODS: Ultrasounds of the left posterolateral arm were performed to measure skin-to-muscle depth in 200 adults receiving subcutaneous immunotherapy. The proportion of patients with a skin-to-muscle depth >13 mm vs. ≤13 mm was assessed and baseline characteristics of the two groups were compared. The proportion of patients with skin-to-muscle depths > 4 mm, 6 mm, 8 mm and 10 mm were also calculated. Multivariable logistic regression was performed to identify predictors of skin-to-muscle depth. RESULTS: Of the 200 patients included in the study, 80% had a skin-to-muscle depth ≤13 mm; the majority (91%) had a skin-to-muscle depth >4 mm. Body mass index was found to be a significant predictor of skin-to-muscle-depth. CONCLUSIONS: Most patients receiving subcutaneous immunotherapy have a skin-to-muscle depth less than the needle length of a standard allergy syringe (13 mm). These patients are at risk of receiving injections intramuscularly, which may increase the risk of anaphylaxis. Using a syringe with a needle length of 4 mm given at a 45° angle to the skin may decrease this risk.

Children under 15 kg with food allergy may be at risk of having epinephrine auto-injectors administered into bone.

BACKGROUND: The Epipen® Jr and Allerject® 0.15 mg are currently the most commonly prescribed epinephrine auto-injectors (EAIs) for the management of anaphylaxis in pediatric patients in North America and Canada. To ensure rapid absorption, it should be administered intramuscularly into the anterolateral aspect of the thigh. We examined whether the 12.7-mm needle length of the Epipen® Jr and Allerject® 0.15 mg is adequate for delivering epinephrine intramuscularly in pediatric patients who weighed <15 kg. METHODS: Consecutive pediatric patients with food allergy weighing <15 kg who required an EAI were included. Ultrasounds of the mid-anterolateral thigh were performed under minimal (min) and maximal (max) pressure. Skin-to-muscle depth (STMD) and skin-to-bone depth (STBD) measurements were completed. Baseline characteristics were compared between patients with a STBDmax <12.7 mm vs. ≥12.7 mm. Linear regression including variables such as age, sex, body mass index (BMI) and race was performed. The proportion of patients with a STBDmax <12.7 mm was compared in those weighing <10 kg vs. 10-14.9 kg. RESULTS: One hundred patients were included; 29 (29%) had STBDmax <12.7 mm. Height (p = 0.02) and weight (p = 0.0002) differed significantly between the two groups. Approximately 19% of those weighing 10-14.9 kg and 60% of those <10 kg had a STBDmax <12.7 mm. In the multivariable regression analysis, BMI was found to be a significant predictor of STBDmax. CONCLUSIONS: A large proportion of children <15 kg prescribed an EAI is at risk of having the auto-injector administered into bone. Since alternative EAIs with shorter needle lengths are not currently available, EAIs should be prescribed with appropriate counselling in this population.

Auto-injector needle length may be inadequate to deliver epinephrine intramuscularly in women with confirmed food allergy.

BACKGROUND: Epinephrine auto-injectors are the standard first aid treatment for anaphylaxis. Intramuscular delivery into the anterolateral aspect of the thigh is recommended for optimal onset of action of epinephrine. The most frequently prescribed auto-injector in North America and Canada is the EpiPen(®), which has a needle length of 15.2 mm. Currently, it is unknown whether this needle length is adequate for intramuscular delivery of epinephrine in adult patients at risk of anaphylaxis. METHODS: One hundred consecutive adult patients with confirmed food allergy requiring an epinephrine auto-injector were recruited. Skin to muscle depth (STMD) at the right mid-anterolateral thigh was measured using ultrasound under minimal (min) and maximum (max) pressure. The EpiPen(®) needle length was considered adequate if STMDmax was ≤15.2 mm. Baseline characteristics including age, gender, ethnicity, and body mass index (BMI) were compared in patients with STMDmax ≤15.2 mm vs. >15.2 mm. RESULTS: The EpiPen(®) needle length of 15.2 mm was inadequate for intramuscular delivery in 19 of the 100 enrolled patients (19%), all of whom were female; 28% of women had a STMDmax >15.2 mm. The mean STMDmax in the ≤15.2-mm and >15.2-mm groups were 9 ± 4 mm and 20 ± 4 mm, respectively (p = 0.0001). Linear regression analysis found BMI to be significantly associated with STMDmax after adjusting for age (p < 0.001). CONCLUSIONS: The needle length of the epinephrine auto-injectors may not be adequate for intramuscular delivery of epinephrine in a large proportion of women with food allergy; this may impact morbidity and mortality from anaphylaxis in this patient population.

The utility of using fiberoptic rhinoscopy in the diagnosis of nasal polyps.

BACKGROUND: Symtomatology of nasal polyps (NP) is relatively non-specific and other nasal conditions that cause nasal may be mistaken for NP. The purpose of this study was to evaluate the accuracy otoscopic (OT) examination in detecting presence of NP by using fiberoptic rhinoscopy (FR) as the gold standard to confirm diagnosis of NP. METHODS: Charts from a single allergy clinic were reviewed for any patient having NP diagnosed by FR. Data collected included gender, age, allergy skin test results, and presence of asthma, aspirin allergy, previous nasal surgeries, intranasal corticosteroid use and leukotriene receptor antagonist use. RESULTS: The OT examination had 44% sensitivity. In this study, more than half (56%) of patients with NP would have had their NP missed if FR had not been performed in addition to the OT examination. CONCLUSIONS: The standard physical examination procedure is often not sufficient to confirm a diagnosis of NP. FR should be considered in the investigation of patients with rhinitis symptoms.

CSACI position statement: safety of topical calcineurin inhibitors in the management of atopic dermatitis in children and adults.

Atopic dermatitis (AD) is a condition frequently encountered in medical practices across the country. Arming ourselves with appropriate and safe treatment modalities to provide relief for this chronic and relapsing inflammatory condition is of utmost importance to our patients and their families. Utilizing topical calcineurin inhibitors (TCIs) for the treatment of AD not responsive to high-potency corticosteroids, or low-potency corticosteroids and localized to the face, eyelids, and skin folds of patients >2 years, is reasonable to include in common practice. Despite the FDA's Black Box warning, to date no evidence has been published linking the TCIs to an increased incidence of malignancy in either children or adults that establishes causation. The Canadian Society of Allergy and Clinical Immunology (CSACI) therefore recognizes that the benefits of TCIs should be carefully weighed with the theoretical risks in advising patients, and acknowledges that long-term studies remain in progress. The safety and efficacy of topical tacrolimus and pimecrolimus should therefore be considered when treating children and adults with AD in Canadian allergy and immunology practices.

An unusual case of bilateral auriculotemporal syndrome presenting to an allergist.

BACKGROUND: Auriculotemporal syndrome (AS) is an uncommon disorder that may present with facial erythema with chewing food. METHODS: We report a patient referred to an allergist to rule out allergy as a reason for food-associated bilateral facial flushing. She was subsequently found to have bilateral AS. RESULTS: The symptoms of AS may overlap those associated with food allergy. There are only a few published cases of bilateral AS. CONCLUSIONS: Allergists should be aware of bilateral AS and the clinical spectrum of this disorder as AS patients may be referred to allergists to rule out food allergy.