Kenneth C. Schuberth

Epidemiologic study of insect allergy in children. II. Effect of accidental stings in allergic children

One hundred eighty-one children with non-life-threatening reactions to insect stings and positive venom skin tests were randomized to treatment (53) or no-treatment (128) groups and followed up clinically and immunologically for at least two years to assess the results of accidental stings. Twenty-eight stings in 17 treated patients and 74 stings in 47 untreated children occurred, leading to one mild reaction in a treated patient, and eight in the no-treatment group (P = NS). No reaction was more serious than the original. Based on IgE antibody changes and skin test results, 87% of the untreated children were stung by an insect to which they had clinical sensitivity by skin test. Vespid skin test sensitivity decreased 10-fold or more in both treated (72%) and untreated (44%) children. Of those with increased sensitivity, congruent to 70% had been stung. These data indicate that the incidence of severe reactions on resting is low in insect-allergic children, and that the majority show decreased skin test sensitivity over time.

A prospective study of the natural history of large local reactions after Hymenoptera stings in children

Large local reactions are a frequent occurrence after insect stings. We prospectively studied the demography, immunology, and significance of these reactions in the pediatric age group. Most children (83%) who have had large local reactions have positive skin test results to one or more venoms. Elevated amounts of venom-specific IgE antibody are usually present. Over 3 to 5 years, allergic sensitivity declines, as evidenced by less positive skin test results and lower levels of antivenom IgE antibodies. Most significantly, of 113 repeat stings, only 2% resulted in a systemic reaction.

An epidemiologic study of insect allergy in children. I. Characteristics of the disease

Of 235 children with a history of allergic reactions to insect stings studied, 59 had severe life-threatening systemic reactions, 123 had mild, non-life-threatening systemic reactions, and 53 had large local reactions. The overall male-female ratio was 2:1. Venom skin tests were positive in approximately 89% of each group. Prior whole body extract therapy increased the likelihood of venom skin test reactivity to multiple insect venoms from 51 to 78%. Venom skin test results did not correlate with the severity of previous allergic reactions. One hundred and nine children with NLTR and positive venom skin tests were entered into one of two groups--venom immunotherapy or observation only. During the first six months the treatment group had the expected fourfold rise in venom-specific IgE antibody titers, whereas the observation group had a decline of the mean IgE titer. Patients in the observation group who were accidentally stung had a transient rise in IgE antibody titers. The small number of accidental stings which occurred in both groups resulted in reactions milder than the original reactions. Although based on preliminary data, venom immunotherapy may not be necessary for some children with previously mild systemic symptoms.

The development of negative skin tests in children treated with venom immunotherapy

Twenty-eight of 62 children (45%) with a history of sting-induced anaphylaxis and initially positive skin tests to venom(s) developed negative venom skin tests to one or more of the venoms used in their treatment after 3 yr or more of immunotherapy. Children who developed negative venom skin tests were less sensitive prior to treatment, as judged by venom skin tests and venom-specific IgE antibody determinations, than children who maintained positive venom skin tests. Levels of venom-specific IgE antibodies declined with time in most children, but to lower levels in those with negative skin tests. Venom-specific IgG antibody levels were similar in both patients with negative skin tests and those with persistently positive skin tests. The development of negative skin tests may reflect a loss of allergic sensitivity, which is sufficient to allow the physician to consider the discontinuation of venom injections.

Assessment of prolonged venom immunotherapy in children

Venom immunotherapy was initiated in 94 children from April 1977 to October 1979. As of February 1983, 66 children had continued receiving treatment and had recent immunologic evaluation. Assessment of prolonged venom treatment included analysis of immunologic parameters, efficacy of treatment, and long-term safety. Venom skin tests, venom-specific IgE antibody levels, and venom-specific IgG antibody levels comprised the immunologic parameters evaluated. A decrease in allergic sensitivity was demonstrated over time in the skin and serum. Forty-three of 57 (75%) children had less positive vespid venom skin tests, and the mean venom-specific IgE antibody level declined to less than the pretreatment value with 3 or more years of yellow jacket venom therapy. Venom-specific IgG antibody measurements rose rapidly after the initiation of venom injections and were maintained for the duration of this evaluation. During a 3- to 6-year period, 200 stings in 49 treated children resulted in only four mild systemic reactions (98% efficacy). The benign nature of interval histories, physical examinations, and laboratory analyses in these children argues optimistically for the safety of prolonged venom immunotherapy.

Peak flow variation in childhood asthma: a three-year analysis.

Measuring peak expiratory flow (PEF) variation has been suggested as a indicator of asthma disease severity and also of nonspecific bronchial hyperreactivity. To test these assumptions, we examined the relationships between PEF variation, methacholine reactivity, symptom scores, and medication requirements in 74 children with tightly controlled allergic asthma. The level of mean diurnal variation (MDV) for the group was 7.1%, which is generally regarded as normal. We found statistically significant correlations between MDV and both methacholine reactivity (r = 0.43, p = 0.0001) and symptom scores (r = 0.28, p = 0.016). These asthma variables were analyzed longitudinally in 33 children who were followed up at 6-month intervals for at least 36 months. Visit-to-visit changes in MDV were generally not reflective of changes in other variables. However, group levels of MDV gradually decreased over time, especially in children with initial MDV of more than 8%. This reduction in group MDV coincided with similar reductions in group medication requirements and methacholine reactivity. We conclude that children with moderately severe asthma that is tightly controlled may have normal levels of PEF variation. The correlation between PEF variation and other asthma variables is statistically significant but too weak to be useful in the treatment of individual patients. In contrast, measurement of MDV may be a useful indicator of disease severity in group studies of asthma.

Value of a multiantigen radioallergosorbent test in diagnosing atopic disease in young children

The purpose of this study was to investigate the value of a new multiantigen radioallergosorbent test, Phadiatop Paediatric, in the diagnosis of atopy in children less than 7 years of age. The diagnosis of atopic disease was established by history, physical examination, total serum IgE concentration, and the results of prick skin tests or radioallergosorbent tests or both, and then compared with the result of the Phadiatop Paediatric test for each patient. One hundred two patients (62 boys) between the ages of 4 months and 7.3 years were enrolled (median age 3.2 years). After the history and physical examination, 42% of the patients were believed to be atopic and 32% to be nonatopic; the diagnosis was uncertain in 26%. Skin prick test reactions to a variety of foods and inhalants were positive in 41 of 63 children tested; results of radioallergosorbent tests were positive in 35 of 61 children. Overall, atopy was diagnosed in 53 children and 49 were found to be nonatopic. When the clinical diagnosis was used as the gold standard, the Phadiatop test resulted in a correct diagnosis of atopy in 49 of 53 cases and of no atopy in 43 of 49 cases: sensitivity = 92%, specificity = 88%, and efficiency = 90%. Although the Phadiatop Paediatric test does not indicate specific sensitivities, it provides the clinician with a useful screening test for atopic disease in children 7 years of age or less, and the researcher with a means of validating atopic populations.

The electrocardiographic diagnosis of left ventricular hypertrophy in apparently normal children

Serial electrocardiographic, vectorcardiographic, and clinical features in 18 children with markedly increased precordial electrocardiographic voltages suggestive of left ventricular hypertrophy are presented. Patients were followed for an average of 31/2 years in order to determine the long-term significance of this finding. Follow-up electrocardiograms were normal in about 30 per cent; precordial voltages were unchanged or increased in about 70 per cent. No child had signs or symptoms of cardiovascular disease, but three subjects (15 per cent) had persistently increased precordial voltages and increased cardiothoracic ratio on chest radiographs. It is suggested that children with increased precordial voltages be followed clinically until the electrocardiogram becomes normal or the diagnosis is otherwise clarified.

Evaluation and Treatment of Insect Sting Allergy

The use of insect venoms for the diagnosis and treatment of individuals with a history of IgE-mediated systemic anaphylactic reactions to insect stings represents a major advance in clinical allergy and immunology. Our experience at The Johns Hopkins Allergic Disease Center at The Good Samaritan Hospital, beginning in 1973, includes evaluation of nearly 1000 insect-allergic adults and children, and the safe and effective treatment of almost half of these patients. In-hospital challenge stings following therapy with appropriate venoms have been carried out in several hundreds of these patients and have resulted in a less than 3% reaction rate. Unfortunately, the decision to use this highly effective venom therapy is not always straightforward, and many clinical situations exist where a lack of information on the natural history of insect allergy prohibits an accurate assessment of the necessity for therapy in the individual patient. In addition, our current diagnostic methods detect prior sensitization to insect venom but do not predict the risk nor the severity of future reactions for the individual patient. Because venom therapy has the disadvantage of patient inconvenience, high cost, unknown incidence of long-term side effects and unknown duration of therapy, the decision for treatment cannot be made lightly. Long-term prospective studies of the natural history of insect allergy are currently in progress and will hopefully clarify the indications and the long-term costs and benefits of venom immunotherapy.