Introduction
There appears to be an increasing prevalence of food allergies in recent decades. In a study that used several national health databases and health care surveys, the prevalence of food allergy in US children was found to be approximately 3.9%, an 18% increase in prevalence between 1997-2007 (1). Sicherer et al. reported that peanut and tree nut allergy in the US had more than tripled from in a similar timeframe (2). A more recent electronic survey indicates that 8% of US children have food allergy (3). Serologic data from the National Health and Nutrition Examination Survey (NHANES) 2005-2006 found an estimated prevalence of clinical food allergy of 2.5% , although this study only examined IgE sensitization to milk, egg, peanut and shrimp rather than clinical reactivity to these foods (4).
Recent large scale epidemiologic studies suggest that there may be higher rates of food allergy in minority groups. Gupta et al. showed that the odds of food allergy were significantly higher among Asian and Black children versus white children (3). Serologic assessment of food allergy from the NHANES study also found that Black race was a risk factor for food allergy (4). In addition, a study looking at food allergen sensitization in children from the National Cooperative Inner City Asthma Study (NCICAS), a majority Black and Hispanic group, found that 45% of children with asthma had evidence of food allergen sensitization, with 19% having IgE levels at ≥50% of the positive predictive value for clinical reactivity to at least 1 food (5). A recent study from a minority urban multiethnic birth cohort showed that self-reported Black race and African ancestry were associated with an increased risk for food sensitization and a high likelihood for multiple food sensitizations (6). Furthermore, a retrospective review of food allergy cases seen in an allergy clinic, which serves primarily Hispanic and Black patients, found high rates of IgE sensitization to foods (7). While these studies suggest that minorities have higher rates of food sensitization, it is important to note that sensitization does not necessarily correlate with clinical disease (8). Currently, there is little data which specifically examines clinical food allergy in urban minorities. Thus, we sought to determine the prevalence and characteristics of food allergy in a general pediatric clinic which serves a low-income minority population.
Methods
Chart review methodology
A retrospective chart review of the electronic medical records from children ages 0 to 21 years attending the hospital-based general pediatric clinic at Mount Sinai Hospital (New York, NY) between July 1, 2008 and July 1, 2010 was performed. Charts with the diagnosis codes 693.1 (food allergy), v15.01 (personal history of allergy to peanut), v15.02 (personal history of allergy to milk products), v15.03 (personal history of allergy to eggs), v14.04 (personal history of allergy to seafood), v15.05 (personal history of allergy to other foods), 995 (anaphylaxis) and/or epinephrine autoinjector prescription were examined. Medical records were reviewed for data on demographics, food allergy history, other allergic history and allergy test results (skin prick test [SPT] and serum specific IgE levels to foods). This study was approved by the Mount Sinai School of Medicine Institutional Review Board with a waiver of consent.
Definitions
Diagnostic algorithms were used to categorize patients into 4 groups. Group 1 was defined by a food-specific IgE level >95% positive predictive value for that food (milk 15 kU/L, egg 7 kU/L, peanut 14 kU/L, tree nuts 15 kU/L,) (9, 10) OR if there was a history of clinical reaction in conjunction with positive testing (SPT ≥3 mm or food specific IgE level >0.35 kU/L). For foods which >95% positive predictive values are not clearly established, the following criteria were used: fish or shellfish 20 kU/L, wheat 26 kU/L, soy 30 kU/L, other food 50 kU/L. Group 2 was defined by a history of convincing, immediate symptoms such as anaphylaxis, hives or urticaria, angioedema, trouble breathing, oral pruritus or throat closing, nausea, vomiting or diarrhea where confirmatory testing was not available (SPT or specific IgE). Group 3 was defined by a history of positive testing (SPT ≥3 mm or food specific IgE level >0.35 kU/L but <95% predictive value for a given food if known or <50kU/L) without a history of clinical reaction. Group 4 was defined by clear food allergy documentation in the medical history with non-specific or unclear symptoms and a lack of and confirmatory testing.
Anaphylaxis was defined as per national guidelines (11). Cutaneous reactions were defined as urticaria, atopic dermatitis, or rash. Respiratory reactions were defined as cough, shortness of breath, wheezing, or nasal congestion. Gastrointestinal reactions were defined as nausea, vomiting, diarrhea, or oral pruritus.
Statistical analysis
Statistical analysis was performed with GraphPad (GraphPad Software, La Jolla, CA). Comparison of categorical data was performed with Fisher's exact test with a 2-tailed p value, while comparison of continuous data was performed with a t-test.
Results
Patient Characteristics
Of the 9184 children ages 0 to 21 years seen in this predominantly minority clinic (table I), the majority of the patients (89%) were insured with Medicaid/Medicaid managed care. The median age was 8 years, and 52% of patients were male (table 1). The charts of 420 subjects met search criteria and medical records were reviewed. A total of 107 charts where excluded, leaving 313 children with food allergy who were included in the final analysis. Sixty charts were excluded because the subjects had been evaluated by an allergist, and food allergy was ruled out. Thirty-three were prescribed an epinephrine autoinjector for non-food allergy reasons (ie. prescribed with palivizumab, insect allergy, allergic reaction of unclear etiology with no food allergy history), 13 subjects had been given a food allergy diagnosis code, but the medical record lacked any other documentation of food allergy or only had documentation of lactose intolerance, and one chart was given only a diagnosis code for anaphylaxis for unclear reasons and lacked any documentation of food allergy.
Table I.
Overall characteristics of patient population and characteristics of food allergic population
| N (%) | |
|---|---|
| Total number of children (ages 0-21 yrs) seen in clinic during time period | 9184 |
| Age | 8 yrs* |
| Gender: | |
| Males | 4741 (52%) |
| Females | 4443 (48%) |
| Race: | |
| African American (Black) | 3460 (37.7%) |
| Other (Multiracial) | 2974 (32.4%) |
| Hispanic/Latino | 1932 (21.0%) |
| Caucasian (White) | 430 (4.7%) |
| Unknown | 184 (2.0%) |
| Asian | 142 (1.5%) |
| Native American | 57 (0.6%) |
| Pacific Islander | 5 (0.1%) |
| Total number of patients with any food allergy | 313 (3.4%) |
| Total number of patients with >1 food allergy | 130 (1.4%) |
| Age at time of this study | 7 yrs (1 yr to 21 yrs)* |
| Age at diagnosis of food allergy | 1 yr (3 mo to 8 yrs)* |
| Gender: | |
| Males | 186 (59%) |
| Females | 127 (41%) |
| Race: | |
| African American (Black) | 161 (51%) |
| Hispanic | 133 (43%) |
| Asian | 5 (2%) |
| Caucasian | 2 (1%) |
| Native American | 2 (1%) |
| Other | 10 (3%) |
| History of food-induced anaphylaxis | 43 (13.7%) |
| Asthma | 157 (50%) |
| # children with asthma seen in ED in the last year | 41 (26%) |
| # children with asthma ever hospitalized for asthma | 30 (19%) |
| Atopic dermatitis | 164 (52%) |
| Allergic rhinitis | 152 (49%) |
median age with range
Prevalence of Food Allergy
The prevalence of physician-documented food allergy in this population was 3.4%, and 1.4% of patients had multiple food allergies (table I). Overall, peanut allergy prevalence was the highest at 1.6%, followed by allergies to shellfish (1.1%), tree nut (0.8%), egg (0.8%), milk (0.5%), fish (0.3%), fruit (0.3%), soy (0.2%) and wheat (0.06%) (table II). The most convincing evidence for food allergy was present in 1.4% of food allergic patients (group 1), with a total of 2.9% of patients (groups 1, 2 and 3) having a likely food allergy and 2.8% having strong evidence for food allergy (groups 1 and 2) (table II). Food allergy was documented by a physician, but medical records suggested that the allergy was less likely, in 0.5% (group 4) (table II). When examined by cases where food allergy is considered likely (groups 1,2,3), allergy to peanut remained most prevalent (1.4%), followed by shellfish (1.0%), egg (0.8%), tree nut (0.7%), fish (0.4%), milk (0.3%), fruit (0.33%), soy (0.18%), and wheat (0.06%) (table II). Regarding groups 1 and 2, which have strong evidence for food allergy, peanut allergy is still the most common (1.2%), followed by shellfish (0.8%), egg (0.7%), tree nut (0.4%), milk (0.29%), fish (0.3%), fruit (0.3%), soy (0.15%), and wheat (0.04%) (table II).
Table II.
Physician-documented food allergy prevalence according to various definitions
| Group 1 history of clinical reaction in conjunction with positive testing (SPT ≥3 mm or food specific IgE level >0.35 kU/L or if there was a food-specific IgE level >95% predictive value | Group 2 history of convincing, immediate symptoms such as anaphylaxis, hives or urticaria, angioedema, trouble breathing, oral pruritis or throat closing, but without testing documentation | Group 3 history of positive testing (SPT ≥3 mm or food specific IgE level >0.35 kU/L but <95% predictive value for a given food if known or <50kU/L) without a documented history of clinical reaction | Group 4 food allergy documented in the medical history, but non-specific or unclear symptoms (ie. rash, itching, diarrhea, nausea, vomiting) and no testing performed | |
| Food allergy patients (n=313) (% out of 9184 total patients) | 127 (1.4%) | 131 (1.4%) | 10 (0.1%) | 45 (0.5%) |
| Groups by food | ||||
| Peanut (n=146) | 62 (0.7%) | 43 (0.5%) | 16 (0.2%) | 25 (0.3%) |
| Shellfish (n=104) | 24 (0.3%) | 48 (0.5%) | 16 (0.2%) | 16 (0.2%) |
| Tree nut (n=77) | 31 (0.3%) | 12 (0.1%) | 27 (0.3%) | 7 (0.1%) |
| Egg (n=74) | 45 (0.5%) | 17 (0.2%) | 5 (0.1%) | 7 (0.1%) |
| Milk (n=45) | 22 (0.2%) | 8 (0.09%) | 1 (0.01%) | 14 (0.2%) |
| Fish (n=32) | 16 (0.2%) | 9 (0.1%) | 5 (0.1%) | 2 (0.02%) |
| Fruit (n=31) | 0 | 23 (0.3%) | 3 (0.03%) | 5 (0.1%) |
| Soy (n=17) | 9 (0.1%) | 5 (0.05%) | 3 (0.03%) | 0 (0%) |
| Wheat (n=6) | 4 (0.04%) | 0 | 2 (0.02%) | 0 |
Characteristics of food allergic patients
Among children with food allergy, the median age was 7 years at the time of the chart review, with a mean age of 1 year at diagnosis when that data was available (table I). The majority of patients were male (59%) (table I). Coexisting allergic disease was common, and approximately half carried a diagnosis of asthma, atopic dermatitis, and/or allergic rhinitis (table I).
The overall rate of food allergy was the same in younger (age ≤ 5 years) and older (age 6 to 21 years) food allergic patients (table III). In younger patients, the three most common food allergies were peanut, egg and milk, while peanut, shellfish and tree nut allergies were most common in older children (Table III). Egg, milk, fish, and wheat allergy were significantly more common in younger patients, while shellfish and fruit allergy were significantly more common in older patients. There were no significant differences in rates of peanut and tree nut allergy with respect to age (table III).
Table III.
Food allergy characteristics by age
| Age 0-5 N (%) | Age 6-21 N (%) | p value | |
|---|---|---|---|
| Overall number of clinic patients in age group | 3740 | 5444 | |
| Overall food allergy | 127 (3.4%) | 186 (3.4%) | 1 |
| >1 food allergy | 67 (1.8%) | 72 (1.3%) | 0.08 |
| Peanut | 57 (1.5%) | 87 (1.6%) | 0.7 |
| Shellfish | 20 (0.5%) | 84 (1.5%) | 0.0001 |
| Tree Nut | 33 (0.8%) | 43 (0.8%) | 0.6 |
| Egg | 49 (1.3%) | 25 (0.4%) | 0.0001 |
| Milk | 39 (1.0%) | 6 (0.1%) | 0.0001 |
| Fish | 20 (0.5%) | 12 (0.2%) | 0.02 |
| Fruit | 6 (0.1%) | 25 (0.5%) | 0.02 |
| Soy | 11 (0.3%) | 6 (0.1%) | 0.05 |
| Wheat | 5 (0.1%) | 1 (0.01%) | 0.004 |
| Of patients with food allergy: | |||
| History of food-induced anaphylaxis | 11 (8.7%) | 33 (18%) | 0.03 |
| Documentation of an epinephrine autoinjector prescription in the medical record | 97 (77%) | 153 (82%) | 0.27 |
| Documentation of an emergency action plan | 68 (54%) | 51 (27%) | 0.0001 |
| Referral to specialty care | 101 (80%) | 109 (59%) | 0.0001 |
| Patients seen by allergy | 77 (61%) | 62 (33%) | 0.0001 |
Peanut allergic patients had significantly higher rates of asthma (62% vs 40%, p<0.0001), oral corticosteroid use for asthma (26% vs 12%, p=0.04) and atopic dermatitis (66% vs 41%, p<0.0001) than those without peanut allergy, although there was no significant difference in rates of any asthma hospitalizations (14% vs 14%, p=1), emergency room visits in the last year for asthma (23% vs 18%, p=0.5), or allergic rhinitis (53% vs 45%, p=0.2). Food allergy patients with shellfish allergy had significantly higher rates of asthma (59% vs 46%, p=0.04) and allergic rhinitis (59% vs 44%, p=0.02). There were no differences in indicators of asthma severity or rates of atopic dermatitis (50% vs 53%, p=0.7) in those with and without shellfish allergy.
Food allergic reaction severity
Overall, a history of food-induced anaphylaxis was seen in 13.7% of all children with physician-documented food allergy (table I). Food-induced anaphylaxis was significantly more common in children ages 6 to 21 years as compared to younger children (table III). There was no difference in rates of food-induced anaphylaxis in terms of race or gender.
Regarding reactions to the different food allergens, anaphylaxis was most commonly seen in children with allergy to peanut (15.1%), fish (12.5%) milk (11.1%), and tree nuts (10.4%). Cutaneous reactions were the most frequent food allergic reaction overall. Angioedema was the second most common reaction (14% of reactions), followed by anaphylaxis (12% of reactions). However, anaphylaxis was the second most commonly reported reaction to peanut, tree nuts, and milk, while angioedema was the second most commonly reported reaction to shellfish and fish. Gastrointestinal and respiratory reactions were less common in this population.
It should be noted that there were a number of peanut, tree nut, and shellfish allergic patients who had never ingested the food, but were avoiding these foods due to positive tests and had unknown clinical reactivity (table II). All these patients had at least one other food allergy, which was evaluated by an allergist. Food reaction history was nevertheless available for most patients with specific food allergies.
Food Allergy Management
Of all patients with food allergy, 67% had documentation of a referral to an allergist, and two-thirds of these patients (45% overall) were actually seen by an allergist (table V). For the remaining patients who were referred, but not seen by an allergist, most never scheduled an appointment or did not show up for their scheduled appointment (table IV). There were no significant differences in regard to gender and race for those patients who received referrals and those who did not. However, significantly more patients age 0-5 years were referred to and seen by an allergist as compared to older patients (table III). Patients allergic to peanut, tree nuts, egg, soy, and wheat were significantly more likely to have been seen by an allergist (table IV). This was expected as younger patients more often had allergies to milk, egg, wheat, and soy (table III). A history of food-induced anaphylaxis was more common in those children who were seen by an allergist (table IV). In addition, children who had evaluation by an allergist were more likely to have additional atopic diseases, including atopic dermatitis and allergic rhinitis.
Table V.
Characteristics of and rates of overall food allergy in Black children vs children of other races seen in clinic
| Black N (%) | Combined other races N (%) | p value | |
|---|---|---|---|
| Total number of patients in general pediatric clinic | 3460 | 5724 | |
| Total with food allergy | 161 (4.7%) | 152 (2.7 %) | 0.0001 |
| >1 food allergy | 61 (1.8%) | 65 (1.1%) | 0.02 |
| Peanut allergy | 73 (2.1%) | 73 (1.3%) | 0.003 |
| Shellfish allergy | 68 (2.0%) | 36 (0.6%) | 0.0001 |
| Tree nut allergy | 43 (1.2%) | 34 (0.6%) | 0.001 |
| Egg allergy | 36 (1.0%) | 38 (0.7%) | 0.05 |
| Milk allergy | 18 (0.5%) | 27 (0.5%) | 0.6 |
| Fish allergy | 17 (0.5%) | 15 (0.3%) | 0.07 |
| Fruit allergy | 17 (0.5%) | 14 (0.2%) | 0.06 |
| Soy allergy | 8 (0.2%) | 9 (0.2%) | 0.3 |
| Wheat allergy | 1 (0.03%) | 5 (0.09%) | 0.4 |
| Patients with food allergy: | 161 | 152 | |
| Males | 88 (55%) | 98 (64%) | 0.08 |
| Females | 73 (45%) | 54 (36%) | |
| Age | 9 yrs (1 yr to 21 yrs)* | 6 yrs (1.3 yrs to 21 yrs)* | 0.003 |
| Age at time of diagnosis | 2 yrs (4 mo to 4 yrs)* | 1 yr (4 mo to 8 yrs)* | 0.1 |
| History of food-induced anaphylaxis | 26 (16.1%) | 17 (11.2%) | 0.3 |
| Documentation of an epinephrine autoinjector | 133 (82.6%) | 117 (77.0%) | 0.3 |
| Documentation of an emergency action plan | 61 (37.9%) | 58 (38.2%) | 1 |
| Referral to specialty care | 107 (66.2%) | 103 (67.8%) | 0.8 |
| Patients seen by allergy | 69 (42.9%) | 70 (46.1%) | 0.6 |
| Asthma | 91 (56.5%) | 66 (43.4%) | 0.03 |
| Asthmatics with emergency room visits in last year | 21 (23.1%) | 20 (30.3%) | 1 |
| Asthmatics ever hospitalized | 11 (12.1%) | 19 (28.8%) | 0.1 |
| Atopic dermatitis | 89 (55.3%) | 75 (49.3%) | 0.3 |
| Allergic rhinitis | 85 (52.8%) | 67 (44.1%) | 0.1 |
median age with range
Table IV.
Food allergy management
| All patients with food allergy (N=313): | |
|---|---|
| Documentation of an epinephrine autoinjector prescription in the medical record | 250 (79.9%) |
| Documentation of an emergency action plan | 119 (38.2%) |
| Referral to specialty care | 210 (67%) |
| Patients seen by specialty care allergist | 141 (45%) |
| Cancelled appointment | 2 (1%) |
| Did not show up at appointment | 34 (11%) |
| Never scheduled an appointment | 30 (9%) |
| Appointment scheduled for a future date | 4 (1%) |
| Seen by allergy (N=141) | Not seen by allergy (N=172) | ||
|---|---|---|---|
| N (%) | N (%) | p value | |
| >1 food allergy | 81 | 50 | 0.0001 |
| Peanut | 81 (57.4%) | 63 (36.6%) | 0.0002 |
| Tree nut | 60 (42.6%) | 17 (9.9%) | 0.0001 |
| Egg allergy | 52 (36.9%) | 22 (12.8%) | 0.0001 |
| Shellfish allergy | 39 (27.7%) | 65 (37.8%) | 0.07 |
| Milk allergy | 24 (17.0%) | 21 (12.2%) | 0.3 |
| Fish allergy | 19 (13.5%) | 13 (7.6%) | 0.1 |
| Soy | 12 (8.7%) | 5 (2.9%) | 0.04 |
| Wheat | 6 (4.3%) | 0 (0.0%) | 0.008 |
| Fruit | 5 (2.9%) | 25 (14.5%) | 0.0003 |
| History of food-induced anaphylaxis | 24 (17.4%) | 16 (9.3%) | 0.04 |
| Documentation of an epinephrine autoinjector | 133 (94%) | 117 (68%) | 0.0001 |
| Documentation of emergency action plan | 118 (84%) | 1 (0.6%) | 0.0001 |
| Asthma | 71 (51.4%) | 83 (48.3%) | 0.6 |
| Atopic Dermatitis | 99 (65.6%) | 63 (36%) | 0.0001 |
| Allergic Rhinitis | 74 (49.0%) | 75 (42.9%) | 0.09 |
Among children with food allergy, the majority of children had documentation of an epinephrine autoinjector prescription (79.9%), and there were no significant differences in epinephrine autoinjector prescription rates with regards to age, race or gender (tables III, V, data not shown). However, food allergic children who had been evaluated by an allergist were more likely to have an epinephrine autoinjector prescription (p<0.0001, table IV). Only food allergic children who had been evaluated by an allergist had documentation of a food allergy action plan in the medical record (table V).
Food allergy characteristics by race
Notable differences in food allergy prevalence and characteristics were seen in Black patients versus patients of other races who were seen in clinic, which consisted primarily of Hispanic and multiracial patients. The overall prevalence of food allergy was significantly higher in Black patients than in patients of other races (4.7% vs 2.7%, p<0.0001). Although the most common food allergens were similar between the 2 groups, Black children had significantly higher rates of peanut, shellfish, and tree nut allergy (table V). In addition, Black children had higher rates of multiple food allergies. While the median age of the Black patients with food allergy was older (age 9 years vs 6 years, p=0.003), there was no significant difference in the median age at diagnosis, gender, or rates of food-induced anaphylaxis. Management of food allergy was comparable between groups, and there were no differences in referral rates for allergy evaluation, rates of patients seen by an allergist, or frequency of documentation of an epinephrine autoinjector prescription and food allergy action plan.
Regarding co-morbid allergic disorders, significantly more Black food allergy patients suffered from asthma than food allergy patients of other races (56.5% vs 43.4%, p=0.03). There were similar rates of emergency room visits and hospitalization for asthma between races. Rates of atopic dermatitis and allergic rhinitis were not significantly different (table V).
Discussion
The aim of this study was to determine the prevalence and characteristics of physician-documented food allergy in a large, low-income population of predominantly Black and Hispanic patients from East Harlem, New York. While there have previously been studies examining IgE sensitization in this population, little has been reported on physician-documented food allergy and features of food allergy. We found the overall prevalence of food allergy to be 3.4% in this population, and this number comprised all patients with documentation of food allergy in the medical record (groups 1-4). This number was somewhat lower than previously reported national estimates (1, 3). When the prevalence of food allergy was determined based on those most likely to have a food allergy (groups 1 and 2), the overall food allergy prevalence was even lower, at only 2.9%. Rates of specific food allergies to peanut, tree nut, and shellfish were comparable to the most recently reported national estimates in this age group (2, 3, 12). However, we found a significantly lower prevalence of milk allergy (0.5%), than that recently reported by Gupta et al. (1.7%) (Χ2, p<0.0001) (3). This may be due to ethnic, cultural, socioeconomic or other differences of this population. Alternatively, the lower prevalence may be due to the fact that this study reports physician-documented food allergy, while Gupta et al. relied on self-reports of food allergy which can overestimate prevalence.
While the majority of children with physician-documented food allergy had an epinephrine autoinjector prescription in the medical record, most did not have documentation of a food allergy action plan, which is recommended by the recent food allergy guidelines (11). The majority of children who had documented food allergy action plans had been evaluated by an allergist, which suggests that general pediatricians are not prescribing or not documenting distribution of food allergy action plans. This is particularly concerning in light of the recent publication by Fleischer et al, which reported that undertreatment of severe reactions even in a population of infants followed at major food allergy centers (13), thus suggesting that the population reported in this study, who largely do not have food allergy action plans, is at considerable risk of undertreatment of anaphylaxis. Educational interventions should be aimed at raising general pediatrician awareness of recent food allergy guidelines, on-line locations where food allergy action plans can be accessed quickly, and the need for epinephrine autoinjector teaching with documentation in the medical record.
Children with peanut allergy had higher rates of asthma and atopic dermatitis than food allergy patients without peanut allergy. Additionally, patients with shellfish allergy had higher rates of asthma and allergic rhinitis compared to non-shellfish allergic patients. This suggests that peanut and shellfish allergy may confer risk for asthma, or vice versa, or may be a sign of more severe atopy in general. Wang et al. reported an increase in asthma morbidity in those patients with food allergen sensitization, specifically peanut sensitization (5). Similarly, Liu et al. reported an increased odds ratio of asthma in those patients with peanut-specific and shrimp-specific IgE sensitization using the NHANES data (4).
Consistent with previous reports, we found that Black children had significantly higher rates of food allergy as compared to children of other races. This group also had higher rates of multiple food allergies. Black children in our population had rates of physician-documented peanut, shellfish, tree nut, and egg allergy higher than those previously published from self-reports of allergy in the general population (3). This is in line with reports of increased odds of elevated peanut-specific and egg-specific IgE levels in patients with a history of African ancestry (6). Rates of asthma were also high in our population of food allergic Black patients, which is consistent with reports of a high degree food allergen sensitization in inner-city asthmatic patients (4, 5). The high rates of asthma, multiple food allergies, and lack of food allergy action planslikely places these children at risk of having food allergic reactions that are not properly managed. Due to the demographic characteristics of this clinic population with few Caucasian and Asian subjects, we were unable to assess the rates and characteristics of food allergy in these populations.
Limitations include the retrospective nature of this study, lack of documented clinical reactivity for foods in all patients, and errors in documentation, such as mis-coding or lack of physician documentation regarding food allergy history or management plans. Parental lack of patient awareness of food allergy is another possibility, in that parents may not be reporting their child's symptoms to the physician, although this seems unlikely given that most over-report food allergies (up to 35% the general population self-report having a food allergy) (14). The physicians of this hospital pediatric clinic receive food allergy education as part of their training, and this hospital is a known referral center for food allergy (Jaffe Food Allergy Institute). Thus, greater awareness of food allergy likely exists at this medical center leading to higher food allergy diagnosis rates than at other institutions, affecting the generalizability of our data. A major limitation in assessing food allergies by race was that 32% of subjects in the clinic had race documented as “other” which is often due to a multiracial status. Therefore, we were unable to identify all patients of African ancestry and the numbers of patients of Hispanic origin is likely significantly higher than reported. Documentation of race has become an increasingly complex issue, even in regards to the United States Census, given our multiracial society (15).
A major strength of this study is the large number of subjects, with over 9000 children attending this pediatric clinic over a two year period. While previous studies have assessed food allergy prevalence in larger numbers of subjects, this represents the largest population of urban, low income, minority children to be reported (1-4, 6, 12, 16-18). As well, use of physician-documentation is a more accurate measure of food allergy than the use of food-specific IgE or self-reported allergy alone. Allergies to all foods were included in the analysis, and the medical records provided additional information regarding severity of reactions, food allergy management and other atopic disorders. Furthermore, almost half of the patients had been evaluated by an allergist and had confirmatory testing for their food allergy.
In conclusion, data has been lacking on food allergies in urban minority patients, and this is the largest study thus far examining physician-documented food allergies in this population. Food allergies appear to be more prevalent in Black children than in children of other races, however the overall prevalence appears lower than expected based on recent reports. Our results also indicate a need for improvements in food allergy management in this population. Although nearly 80% of children with physician-documented food allergy had epinephrine autoinjector prescriptions in the medical record, only 40% had an emergency action plan for food allergy documented. Primary care physicians should have more education on the use and availability of action plans, and all physicians should provide them to these patients and clearly document their distribution and explanation in the medical record. Finally, only 46% of patients had their food allergy evaluation by an allergy specialist. Many food allergy patients were referred more than once to an allergist (data not shown), and were never seen because an appointment was not scheduled or the child did not show up for the scheduled appointment. Patients and physicians should be aware of the importance of an accurate diagnosis of food allergy as unnecessary avoidance of foods may have nutritional, development and social impacts. Furthermore, food allergy education is essential to ensure appropriate food allergen avoidance and emergency management for allergic reactions. Additional studies are needed to further examine the racial and ethnic differences in food allergy prevalence and triggers, identify possible risk factors in these groups, and improve food allergy management.
Figure Ia.
Rates of anaphylaxis in patients with each food allergy
Figure Ib.
Types of food allergic reactions overall and per food.
Acknowledgments
Funding support: Julie Wang, MD is funded in part by a grant from the National Institutes of Health/National Institute of Allergy and Infectious Diseases (K23 AI083883).
Abbreviations
- NCICAS
National Cooperative Inner City Asthma Study
- NHANES
National Health and Nutrition Examination Survey
- SPT
skin prick test
Footnotes
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