Total population:
Table 1: Demographics
Characteristic
|
% Overall (n=74)
|
% Sesame (n=41)
|
% Legume (n=33)
|
Male Sex, N (%)
|
35 (47.3)
|
20 (48.78)
|
15 (45.45)
|
Race, N (%)
|
|
|
|
White
|
57 (77.03)
|
35 (85.37)
|
22 (66.67)
|
African American
|
2 (2.70)
|
1 (2.44)
|
1 (3.03)
|
Hispanic
|
2 (2.70)
|
1 (2.44)
|
1 (3.03)
|
Asian
|
2 (2.70)
|
0 (0.00)
|
2 (6.06)
|
Other
|
11 (14.86)
|
4 (9.76)
|
7 (21.21)
|
Median age (years) at time of challenge
|
6.12
|
5.91
|
6.15
|
Personal Atopic History, N (%)
|
|
|
|
Eczema
|
53 (71.62)
|
32 (78.05)
|
22 (66.67)
|
Asthma
|
20 (27.03)
|
10 (24.39)
|
10 (30.30)
|
Allergic Rhinitis
|
38 (51.35)
|
23 (56.10)
|
15 (45.45)
|
History of other Food Allergy
|
60 (81.08)
|
38 (92.68)
|
22 (66.67)
|
Preventively avoiding, N (%)
|
40 (54.05)
|
24 (58.54)
|
16 (48.48)
|
Seventy-four OFCs were reviewed, comprised of thirty-three legume challenges and forty-one sesame challenges (Table 1). Of the total population, 47.3% participants were male, the median age at the OFC was 6.12 years (range 0.55 to 20.45 years). Patients often had history of atopic disease, with eczema and multiple food allergies being most common (Table 1.
The median age at the time of OFC, food sIgE level at the time of OFC, and OFC pass rates are presented in Table 2. The overall OFC pass rate was high at 71.62%. Twenty-eight subjects (84.85%) passed OFC to legumes, while twenty-five (60.98%) passed OFC to sesame.
Of the failed challenges overall, 52.4% of the reactions consisted of cutaneous symptoms only, 14.3% were gastrointestinal symptoms alone, and 33.3% were anaphylaxis (defined as a reaction involving two or more organ systems (Additional Figure 1A). Medications required are shown in Additional Figure 1B. Overall, 48.6% of subjects who failed a sesame or legume OFC required epinephrine. These data underscore the risk of anaphylaxis to sesame and legumes.
Logistic regression analyses were performed to examine clinical predictors of OFC outcomes. A model including history of a reaction to the food, age at the time of OFC, personal history of atopic dermatitis, personal history of asthma, personal history of allergic rhinitis, and sIgE at the time of OFC did not significantly predict OFC outcome.
Table 2: Descriptive statistics of overall population, legume subjects, and sesame subjects referencing median age, pass rate, median IgE level, and level of significance. P values represent statistical significance comparing median IgE level between the cases that passed and failed an Oral Food Challenge.
|
# of patients
|
Median Age
|
Pass Rate
|
Median IgE Level, all, (kUa/L)
|
Median IgE Level Fail, (kUa/L)
|
Median IgE Level, Pass, (kUa/L)
|
P value
|
All Challenges
|
74
|
6.83
|
71.62%
|
2
|
2.71
|
1.66
|
0.0886
|
Legume
|
33
|
6.12
|
84.85%
|
1.44
|
3.04
|
1.41
|
0.1512
|
Sesame
|
41
|
5.9
|
60.98%
|
2.34
|
2.7
|
2.28
|
0.4781
|
Sesame Oral Food Challenges:
Table 3: Sesame OFC pass rate within sIgE quartile ranges
Sesame IgE
|
Total
|
Passed
|
Failed
|
Percent Passed
|
Total
|
41
|
25
|
16
|
60.98%
|
Less than 0.35
|
7
|
5
|
2
|
71.43%
|
0.35 to 1.47
|
9
|
4
|
5
|
44.44%
|
1.47 to 3.91
|
9
|
6
|
3
|
66.67%
|
3.91 to 6.66
|
8
|
7
|
1
|
87.50%
|
6.66 to 59.1
|
8
|
3
|
5
|
37.50%
|
Forty-one sesame OFCs were reviewed. Demographic data of patients undergoing sesame OFC were similar to the overall population (Table 1). Of patients challenged to sesame, 41.46% were avoiding sesame due to a history of clinical reactivity upon ingestion with evidence of sensitization on skin prick testing or serum sIgE testing. Twenty-four participants (58.54%) were preventatively avoiding sesame without a history of prior ingestion due to another food allergy (i.e. peanut) or evidence of sensitization to sesame on testing performed prior to oral exposure.
The majority (60.98%) of patients passed a sesame OFC. Among patients who failed a sesame OFC, 50% had a reaction characterized by cutaneous symptoms only, 12% with gastrointestinal symptoms only, and 38% experienced anaphylaxis. Of the sixteen subjects who failed a sesame OFC, 56% required at least one dose of epinephrine (Figure 1A, 1B). There was a significant difference in the number of individuals with a personal history of atopic dermatitis between subjects who passed and failed a sesame OFC. Among those who passed a sesame OFC, 88% had a personal history of atopic dermatitis, whereas only 50% of those who failed had a personal history of atopic dermatitis (p=0.012). Logistic regression analysis found that a personal history of atopic dermatitis was the only significant predictor of a passed sesame OFC. The odds of a failed OFC to sesame among subjects with a personal history of atopic dermatitis was 0.14 times that of subjects without a personal history of atopic dermatitis (p=0.021). A personal history of asthma, a personal history of allergic rhinitis, and age at OFC did not significantly differ between subjects who passed and failed sesame OFC.
We next compared patients with a prior reaction history compared to those that were preventatively avoiding sesame. Over half of the patients challenged to sesame had no previous history of a reaction to sesame (58.54%), and there was no significant difference between subjects who passed and failed sesame OFC based on previous reaction history (P=0.124). Of the seventeen subjects who had a history of a reaction to sesame, 47% passed and 53% failed a sesame OFC. Among those who failed, symptoms experienced and treatment required are presented in Figure 1.
Of the remaining twenty-four subjects preventively avoiding sesame, 71% passed and 29% failed a sesame OFC. Of those who failed a sesame OFC, patients with previous reaction history demonstrated similar rates of anaphylaxis compared to those preventatively avoiding (43% vs 33%, p=0.28). Interestingly, although many of these reactions began with cutaneous symptoms only, many of these patients did not respond to antihistamine administration alone and needed an escalation in therapy (Additional Figure 2A).
The median sIgE value for all subjects challenged to sesame was 2.34 kUa/L (range 0.12-59.1 kUa/L). Patients who passed a sesame OFC had a median sIgE level of 2.28 kUa/L, and subjects who failed had a median sIgE level of 2.70 kUa/L. Sesame sIgE did not significantly differ between individuals that passed and failed an OFC to sesame (Table 2 and Figure 2, P=0.4781).
Patients challenged to sesame were organized into two groups based on undetectable IgE values (<0.35) and those with positive IgE values (>0.35), and the pass rates of the subsequent challenges were recorded. The positive sesame sIgE levels were subsequently categorized into quartiles (25% -1.47 kUa/L, 50% - 3.91 kUa/L, 75% - 6.66 kUa/L), (Table 3). The highest percentage of passed OFCs was identified for sIgE levels between 3.91 and 6.66 kUa/L (87.5%), while the lowest percentage of passed OFCs (37.5%) came from subjects with the greatest range of IgE values, (6.66 to 59.1 kUa/L).
Legume Oral Food Challenges:
Table 4: Legume OFC pass rates within sIgE quartile ranges
Legume IgE
|
Total
|
Passed
|
Failed
|
Percent Passed
|
Total
|
33
|
28
|
5
|
84.85%
|
Less than 0.35
|
9
|
9
|
0
|
100.00%
|
0.35 to 1.26
|
6
|
4
|
2
|
66.67%
|
1.26 to 2.54
|
6
|
6
|
0
|
100.00%
|
2.54 to 5.86
|
6
|
5
|
1
|
83.33%
|
5.86 to 62.8
|
6
|
4
|
2
|
66.67%
|
Thirty-three OFCs to legumes were reviewed. During the challenge patients consumed either beans, peas, or lentils at increasing doses. Demographic data is presented in Table 1 and is similar to the overall cohort. There were no significant differences in age at time of challenge or personal history of atopy between individuals who passed or failed legume OFC.
Twenty-eight of thirty-three subjects (84.9%) passed an OFC to legume. Of the five patients who failed a legume OFC (N=5), 60% had an allergic reaction consisting of cutaneous symptoms only, 20% presented with gastrointestinal symptoms only, and 20% of patients experienced anaphylaxis. Of the failed challenges, only one patient (20%) required epinephrine (Figure 3A).
Among patients challenged to legume, fifteen patients (45.46%) had no previous history of a reaction to peas, beans, or lentils (i.e. legumes). There was no significant difference in history of previous reaction to legume between subjects who passed or failed an OFC (P=0.346). Of the eighteen patients (54.54%) with a history of a reaction to legume, fourteen (77.78%) passed and four (22.22%) failed a legume OFC. Symptoms and treatments are presented in figure 3B and 3C.
Of the sixteen patients without a history of a reaction to legume, the one (6.67%) failed OFC was characterized by cutaneous symptoms alone and were treated with an antihistamine. The remaining fourteen subjects (93.33%) all passed their legume OFC.
Patients who passed a legume OFC had a median legume sIgE level of 1.41 kUa/L, and subjects who failed a legume OFC had a median legume sIgE level of 3.04 kUa/L (Table 2, P=0.1512 and Figure 4).
The legume sIgE values were divided into quartiles and the rates of passing a legume OFC, based on sIgE quartile, were examined (Table 4). There was a 100% legume OFC pass rate for individuals with a legume sIgE less than 0.35 kUa/L and for those with a level between 1.26 and 2.54 kUa/L. The lowest percentage of passed food challenges (66.67%), came from subjects within the upper quartile of legume sIgE values, between 5.86 and 62.8 kUa/L. Regardless of legume sIgE level, over 60% of legume OFCs were passed.