Anahita F. Dioun

Antibiotic desensitization for the allergic patient: 5 years of experience and practice

Background Antibiotic desensitization is an option for patients with suspected IgE-mediated antibiotic allergy when no other alternative exists for treating life-threatening bacterial infections. However, there are limited data describing the outcomes of this procedure with newer, commonly used antibiotics. Objective To evaluate the safety and utility of antibiotic desensitization. Methods We retrospectively reviewed the medical records of all patients undergoing antibiotic desensitization in our institution between November 1996 and November 2001. Results There were a total of 57 desensitizations performed in 21 patients. The mean age of the patients was 22.8 years (range, 1.9-44.5 years) and 15 (71%) were female. Nineteen (90%) of the 21 patients had been diagnosed as having cystic fibrosis. In 33 (100%) of 33 desensitizations to unique antibiotics that occurred during the study period, the indication for desensitization was a history suggestive of an IgE-mediated reaction to the antibiotic and/or a positive skin test result to the antibiotic or a known cross-reactive antibiotic. Desensitizations were performed to 12 different antibiotics. Successful outcomes were achieved in 43 desensitizations (75%). Of the 11 cases (19%) that were terminated due to an allergic reaction, there were no fatalities, intubations, or other aggressive interventions besides the use of epinephrine, antihistamines, and corticosteroids. In 7 of 11 unsuccessful desensitizations, a non-IgE mechanism appeared to be responsible for the allergic reaction. Conclusions Antibiotic desensitization is a useful option when treating patients with life-threatening infections who must receive antibiotics to which they have an IgE-mediated allergy. These data indicate that in most cases, patients with presumed IgE-mediated antibiotic allergy may safely receive antibiotics after desensitization.

Predicting food challenge outcomes for baked milk: role of specific IgE and skin prick testing

BACKGROUND Cows milk allergy is the most common food allergy in childhood. Many children with IgE-mediated cows milk allergy may tolerate baked milk products, but few data exist on predictors of outcomes of baked milk challenges. OBJECTIVE To determine the relation of milk protein allergen specific IgE (sIgE) levels and skin prick test (SPT) wheal size with baked milk challenge outcomes. METHODS A retrospective medical record review was conducted of 35 baked milk challenges. SPT results, sIgE levels, demographic characteristics, and food challenge results were analyzed. RESULTS Thirty-five children underwent open challenges to baked milk and 29 (83%) passed. Of those who failed, 3 (50%) passed the initial clinic challenge but developed symptoms to ongoing exposure at home, days to months later. One child who ultimately failed at home required epinephrine. Compared with those who passed, children who failed were younger (median age, 8.9 and 3.7 years, respectively; P = .02). Children with a milk SPT wheal less than 12 mm were more than 90% likely to pass a baked milk challenge, and no child with a milk SPT wheal less than 7 mm failed a baked milk challenge. We were also able to establish more than 90% predictive values for passing baked milk challenges with a casein SPT wheal of 9 mm, a milk sIgE level of 1.0 kU/L, and a casein sIgE level of 0.9 kU/L. CONCLUSION Most children allergic to cows milk tolerated baked milk. Milk protein SPT wheal may be more reliable than sIgE level in predicting outcomes of baked milk challenges. It is important to be aware of the possibility of late reactions to ongoing baked milk exposure.

Role of specific IgE and skin-prick testing in predicting food challenge results to baked egg

Previous studies suggest that children with egg allergy may be able to tolerate baked egg. Reliable predictors of a successful baked egg challenge are not well established. We examined egg white-specific IgE levels, skin-prick test (SPT) results, and age as predictors of baked egg oral food challenge (OFC) outcomes. We conducted a retrospective chart review of children, aged 2-18 years, receiving an egg white-specific IgE level, SPT, and OFC to baked egg from 2008 to 2010. Fifty-two oral baked egg challenges were conducted. Of the 52 challenges, 83% (n = 43) passed and 17% (n = 9) failed, including 2 having anaphylaxis. Median SPT wheal size was 12 mm (range, 0-35 mm) for passed challenges and 17 mm (range, 10-30 mm) for failed challenges (p = 0.091). The negative predictive value for passing the OFC was 100% (9 of 9) if SPT wheal size was <10 mm. Median egg white-specific IgE was 2.02 kU/L (range, <0.35-13.00 kU/L) for passed challenges and 1.52 kU/L (range, 0.51-6.10 kU/L) for failed challenges (p = 0.660). Receiver operating characteristic (ROC) curve analysis for SPT revealed an area under the curve (AUC) of 0.64. ROC curve analysis for egg white-specific IgE revealed an AUC of 0.63. There was no significant difference in age between patients who failed and those who passed (median = 8.8 years versus 7.0 years; p = 0.721). Based on our sample, SPT, egg white-specific IgE and age are not good predictors of passing a baked egg challenge. However, there was a trend for more predictability with SPT wheal size.

Characterizing the relationship between sesame, coconut, and nut allergy in children

Stutius LM, Sheehan WJ, Rangsithienchai P, Bharmanee A, Scott JE, Young MC, Dioun AF, Schneider LC, Phipatanakul W. Characterizing the relationship between sesame, coconut, and nut allergy in children.
Pediatr Allergy Immunol 2010: 21: 1114–1118.
© 2010 John Wiley & Sons A/S

Is maternal age at delivery related to childhood food allergy

The prevalence of food allergies is increasing. Concurrently, the average maternal age at birth is also increasing. We conducted a preliminary study to evaluate whether maternal age at the time of delivery is associated with a food allergy in children. Case and control patients were identified among consecutive patients seen by one of us (AD) in the Allergy/Immunology program at the Childrens Hospital Boston between 11/1/98 and 2/28/00. Case patients were born in Massachusetts and had evidence of clinical sensitivity and IgE to one or more food allergens (n = 58). Control patients were those born in Massachusetts who had a negative skin test and/or RAST to inhalant and/or food allergens (n = 96). A second comparison group consisted of all live births in Massachusetts in 1999 (n = 80,866). Information on maternal age at birth was missing from 3/58 (5%) of patients with a food allergy and 4/96 (4%) of the control patients, so these patients were not included in the analysis. The proportion of children whose mother was aged 30 and over at their birth was significantly higher in children with a food allergy than control patients (78% vs. 55% p = 0.005) and higher than all births in Massachusetts (78% vs. 53% p = 0.0002). Mothers of children with a food allergy had about three times greater odds of being aged 30 or over at the time of delivery than mothers in either of the comparison groups. Further exploration of the data using logistic regression showed that maternal age over 30 at delivery and being first born were independent predictors of the child having a food allergy. In this study, the presence of a food allergy in children was related to older maternal age at delivery. Additional studies are needed to further evaluate this relationship and its potential implication in preventive strategies for food allergies in children.

Adverse reactions to vitamin B12 injections due to benzyl alcohol sensitivity: successful treatment with intranasal cyanocobalamin

References 1. Laxenaire MC, Mertes PM. Anaphylaxis during anaesthesia. Results of a two-year survey in France. Br J Anaesth 2001;87:549–558. 2. Banchereau J, Steinman RM. Dendritic cells and the control of immunity. Nature 1998;392:245–252. 3. Bernard J, Ittelet D, Christoph A, Potron G, Adjizian JC, Kochman S et al. Adherent-free generation of functional dendritic cells from purified blood monocytes in view of potential clinical use. Hematol Cell Ther 1998;40:17–26. 4. Pichler WJ, Yawalkar N. Allergic reactions to drugs: involvement of T cells. Thorax 2000;55(Suppl. 2): S61–S65. Adverse reactions to vitamin B12 injections due to benzyl alcohol sensitivity: successful treatment with intranasal cyanocobalamin

Successful rifampin desensitization in a pediatric patient with latent tuberculosis

To the Editor, Rifampin is rarely associated with hypersensitivity reactions (1). As there are situations in which alternative therapies are not possible, readministration of this drug by desensitization must be considered in some patients. This is particularly true in the setting of latent tuberculosis where treatment options are limited. Desensitization induces a temporary state of tolerance to a medication that has provoked a hypersensitivity response by administering incremental doses of the medication until the total cumulative therapeutic dose is achieved (2). This tolerance can be maintained as long as the medication is administered at regular intervals without discontinuation or missed doses (3). Case reports describing successful desensitization to rifampin in adult patients have been published in the past describing different techniques with protocols spanning seven or more days to a few hours (4–6). There is a single case report of rifampin desensitization in a pediatric patient during which the patient suffered reactions despite pre-medication with antihistamines and steroids. Although the authors briefly mention using a modified penicillin protocol, they do not provide any information about the number of steps, dosing, or total duration of the protocol (7). We report successful rapid desensitization to rifampin in a pediatric patient with latent tuberculosis. We also describe a new post-desensitization dosing regimen which combines therapeutic efficacy with safe dosing interval. A 10-yr-old, 53 kg, male with a history of G6PD deficiency was diagnosed with latent tuberculosis after immigration from West Africa. The diagnosis was confirmed with a positive PPD skin test and T-SPOT Gold tuberculosis QuantiFERON test in the context of a negative chest X-ray. The patient’s G6PD deficiency conferred a risk of hemolysis with administration of isoniazid; therefore, therapy was initiated with rifampin. Six hours after his first 600 mg oral dose of rifampin, the patient developed a diffuse, pruritic, non-blistering urticarial skin rash. He had no additional signs of hypersensitivity. He was treated with Benadryl, and the rash resolved within 3 days after discontinuation of rifampin. In light of this drug reaction, his therapy was changed to isoniazid 300 mg daily. However, after taking the first dose of isoniazid, he developed a diffuse pruritic rash without systemic symptoms. Isoniazid was discontinued, and the rash resolved in 2–3 days. Isoniazid is the recommended first-line treatment in children and adolescents for latent tuberculosis. In pediatric patients who cannot tolerate isoniazid therapy, the AAP recommends rifampin at a dosage of 10–20 mg/kg (8). Given our patient’s underlying history of G6PD deficiency and hypersensitivity to both isoniazid and rifampin, we pursued skin testing to rifampin. This was performed based on published protocols where the highest non-irritating intradermal concentration of rifampin in healthy subjects was 0.002 mg/ml (9). Histamine was utilized as a positive control, and saline as a negative control. Skin prick testing with rifampin at 2 mg/ml concentration was negative. The patient had positive intradermal testing to 0.05 ml of rifampin at the concentration of 0.002 mg/ml with a wheal of 9 mm and flare of 15 mm. Intradermal testing to the saline control was negative. Given these results and his history, IgE-mediated hypersensitivity to rifampin was deemed likely, and desensitization to this drug was pursued. The patient was hospitalized in an ICU step-down unit for a rapid oral desensitization to rifampin. The recommended dose of rifampin for treatment of latent tuberculosis is 600 mg (10–20 mg/kg) daily, but the short half-life of 3 h precludes maintenance of the desensitized state with once-daily dosing. Administering a lower dose at more frequent intervals while keeping the total daily dose at 600 mg was not appropriate because achieving optimal peak drug serum concentrations is important in this drug’s activity against tuberculosis and preventing resistance (10). Therefore, we aimed for a postdesensitization rifampin regimen of 600 mg in the morning followed by 300 mg at night. This daily rifampin dose of

Management of Multiple Drug Allergies in Children

Children with multiple drug allergies are likely to require treatment with one or more of the drugs to which they may have had a reaction, when there is no alternate effective drug available. Detailed review of their history and/or use of appropriate diagnostic studies will help determine the potential safety of readministering the desired drug as well as the method for its readministration, most likely in the form of a drug challenge or desensitization. A practical approach to the diagnosis and treatment of children with multiple drug allergies is described in this review.

Antibiotic desensitization for the allergic patient: 5 Years of experience and practice

BACKGROUND Antibiotic desensitization is an option for patients with suspected IgE-mediated antibiotic allergy when no other alternative exists for treating life-threatening bacterial infections. However, there are limited data describing the outcomes of this procedure with newer, commonly used antibiotics. OBJECTIVE To evaluate the safety and utility of antibiotic desensitization. METHODS We retrospectively reviewed the medical records of all patients undergoing antibiotic desensitization in our institution between November 1996 and November 2001. RESULTS There were a total of 57 desensitizations performed in 21 patients. The mean age of the patients was 22.8 years (range, 1.9-44.5 years) and 15 (71%) were female. Nineteen (90%) of the 21 patients had been diagnosed as having cystic fibrosis. In 33 (100%) of 33 desensitizations to unique antibiotics that occurred during the study period, the indication for desensitization was a history suggestive of an IgE-mediated reaction to the antibiotic and/or a positive skin test result to the antibiotic or a known cross-reactive antibiotic. Desensitizations were performed to 12 different antibiotics. Successful outcomes were achieved in 43 desensitizations (75%). Of the 11 cases (19%) that were terminated due to an allergic reaction, there were no fatalities, intubations, or other aggressive interventions besides the use of epinephrine, antihistamines, and corticosteroids. In 7 of 11 unsuccessful desensitizations, a non-IgE mechanism appeared to be responsible for the allergic reaction. CONCLUSIONS Antibiotic desensitization is a useful option when treating patients with life-threatening infections who must receive antibiotics to which they have an IgE-mediated allergy. These data indicate that in most cases, patients with presumed IgE-mediated antibiotic allergy may safely receive antibiotics after desensitization.