Overall positivity rate of sIgE with inhaled and food allergens
The positivity rate of serum inhaled allergens in children with AR was 80.05% (999/1248), significantly higher than the food allergen positivity rate of 66.19% (826/1248) (c2 = 61.00, P < 0.01). The most common inhaled allergens were D. pteronyssinus (65.38%, 816/1248), mold mix (25.56%, 319/1248), house dust (20.67%, 258/1248), and dog hair (13.94%, 174/1248). Similarly, among the food allergens, positivity of sIgE to cow’s milk (30.21%, 377/1248), cashew nut (27.9%, 349/1248), egg (22.68%, 283/1248), and beef (12.98%,162/1248) was more frequent (Table 1).
Table 1. The positivity rate of sIgE with inhaled and food allergens
Allergens
|
Negative (Grade 0)
|
Positive
|
Grade I
|
Grade II
|
Grade III
|
Grade IV
|
Grade V
|
Grade VI
|
Total
|
Ranking
|
Inhaled
|
D. pteronyssinus
|
432 (34.62%)
|
33
|
95
|
234
|
225
|
105
|
124
|
816 (65.38%)
|
1
|
House dust
|
990 (79.33%)
|
105
|
141
|
9
|
2
|
0
|
1
|
258 (20.67%)
|
6
|
Mulberry
|
1215 (97.36%)
|
12
|
18
|
2
|
1
|
0
|
0
|
33 (2.64%)
|
17
|
Cat dander
|
1107 (88.70%)
|
20
|
65
|
46
|
7
|
0
|
3
|
141 (11.30%)
|
10
|
Dog hair
|
1074 (86.06%)
|
82
|
86
|
4
|
2
|
0
|
0
|
174 (13.94%)
|
7
|
Cockroach
|
1201 (96.23%)
|
27
|
17
|
2
|
0
|
1
|
0
|
47 (3.77%)
|
15
|
Amaranth
|
1168 (93.59%)
|
29
|
26
|
20
|
5
|
0
|
0
|
80 (6.41%)
|
13
|
Mold mix
|
929 (74.44%)
|
46
|
95
|
134
|
36
|
7
|
1
|
319 (25.56%)
|
4
|
Grass mix
|
1217 (97.52%)
|
13
|
11
|
6
|
1
|
0
|
0
|
31 (2.48%)
|
18
|
|
Tree pollen mix
|
1175 (94.15%)
|
34
|
32
|
5
|
1
|
1
|
0
|
73 (5.85%)
|
14
|
Food
|
Egg
|
965 (77.32%)
|
148
|
115
|
15
|
1
|
4
|
0
|
283 (22.68%)
|
5
|
Cow’s milk
|
871 (69.79%)
|
152
|
210
|
13
|
1
|
0
|
1
|
377 (30.21%)
|
2
|
Shrimp
|
1136 (91.03%)
|
56
|
29
|
20
|
3
|
0
|
4
|
112 (8.97%)
|
11
|
Beef
|
1086 (87.02%)
|
120
|
42
|
0
|
0
|
0
|
0
|
162 (12.98%)
|
8
|
Shellfish
|
1203 (96.39%)
|
41
|
3
|
1
|
0
|
0
|
0
|
45 (3.61%)
|
16
|
Crab
|
1092 (87.50%)
|
70
|
46
|
26
|
8
|
1
|
5
|
156 (12.50%)
|
9
|
Mango
|
1161 (93.03%)
|
68
|
16
|
3
|
0
|
0
|
0
|
87 (6.97%)
|
12
|
Cashew nut
|
899 (72.04%)
|
163
|
132
|
41
|
13
|
0
|
0
|
349 (27.96%)
|
3
|
Pineapple
|
1224 (98.08%)
|
16
|
8
|
0
|
0
|
0
|
0
|
24 (1.92%)
|
19
|
Allergen sensitization in different sex and age groups
The positivity rates of overall inhaled allergens in both boys (81.05%, 663/818) and girls (78.14%, 336/430) were significantly higher than the positivity rates of food allergens in boys (65.77%, 538/818) and girls (66.98%, 288/430) (c2 = 48.93; 13.46, P < 0.01) (Table 2). There was no sex difference in the overall positive rate of inhaled (81.05% vs. 78.14%) and food allergens (65.77% vs. 66.98%) (c2 = 1.50; 0.18, P > 0.05) (Table 2). However, the sIgE positivity rates of mulberry, cat dander, dog hair, amaranth, beef, and crab were higher among males than females (Table 3).
Table 2. The positivity rates of overall inhaled and food allergens compared by sex
|
Inhaled
|
Food
|
Positive
|
Negative
|
Positive
|
Negative
|
Males
|
663 (81.05%)
|
155 (18.95%)
|
538 (65.77%)
|
280 (34.23%)
|
Females
|
336 (78.14%)
|
94 (21.86%)
|
288 (66.98%)
|
142 (33.02%)
|
Table 3. Allergen sensitization compared by sex
Allergens
|
Number of sIgE-positive patients (%)
|
Chi-squared (c2)
|
P value
|
Male
|
Female
|
D. pteronyssinus
|
542(66.26%)
|
274(63.72%)
|
0.8
|
>0.05
|
House dust
|
169(20.66%)
|
89(20.70%)
|
0
|
>0.05
|
Mulberry
|
29(3.55%)
|
4(0.93%)
|
7.49
|
<0.05
|
Cat dander
|
105(12.84%)
|
36(8.37%)
|
5.6
|
<0.05
|
Dog hair
|
130(15.89%)
|
44(10.23%)
|
7.53
|
<0.05
|
Cockroach
|
33(4.03%)
|
14(3.26%)
|
0.47
|
>0.05
|
Amaranth
|
64(7.82%)
|
16(3.72%)
|
7.91
|
<0.01
|
Mold mix
|
208(25.43%)
|
111(25.81%)
|
0.02
|
>0.05
|
Grass mix
|
22(2.69%)
|
9(2.09%)
|
0.3
|
>0.05
|
Tree pollen mix
|
50(6.11%)
|
23(5.34%)
|
3.22
|
>0.05
|
Egg
|
173(21.15%)
|
110(25.58%)
|
3.16
|
>0.05
|
Cow’s milk
|
258(31.54%)
|
119(27.67%)
|
2
|
>0.05
|
Shrimp
|
82(10.02%)
|
30(6.98%)
|
3.21
|
>0.05
|
Beef
|
118(14.43%)
|
44(10.23%)
|
4.39
|
<0.05
|
Shellfish
|
25(3.06%)
|
20(4.65%)
|
2.06
|
>0.05
|
Crab
|
117(14.30%)
|
39(9.07%)
|
7.06
|
<0.05
|
Mango
|
54(6.60%)
|
33 (7.67%)
|
0.5
|
>0.05
|
Cashew nut
|
242(29.58%)
|
107 (24.88%)
|
3.09
|
>0.05
|
Pineapple
|
18(2.20%)
|
6 (1.39%)
|
0.97
|
>0.05
|
All children were divided into three groups based on age (1–3, 4–7, and 8–14 yr). The sensitization to total inhaled and food allergens was significantly different among age groups (c2 = 77.34; 37.97, P < 0.01) (Table 4). The positivity rate of inhaled allergens increased with age, while conversely, the positivity rate of food allergens decreased with age. The positivity rate of inhaled allergens in children aged 1–3 yr was lower than that of food allergens (c2 = 11.11, P < 0.01). The opposite trend was observed in children aged 8–14 yr (c2 = 157.45, P < 0.01). The inhaled allergen sIgE positivity rates of D. pteronyssinus, house dust, cat dander, amaranth, and mixed mold were low in the 1–3 yr group and increased with age, while the positivity rates of egg, cow’s milk, crab, and cashew showed the opposite trend (Table 5).
Table 4. Allergen sensitization in different age groups
Allergens
|
Number of sIgE-positive patients (%)
|
Chi-squared (c2)
|
P value
|
1–3 yr
|
4–7 yr
|
8–14 yr
|
Number of patients
|
81
|
501
|
666
|
|
|
Inhaled
|
49 (60.49%)
|
357 (71.26%)
|
593 (89.04%)
|
77.34
|
<0.01
|
Food
|
68 (83.95%)
|
366 (73.05%)
|
392 (58.86%)
|
37.97
|
<0.01
|
Table 5. The positivity rate of sIgE in different age groups
Allergens
|
Number of sIgE-positive patients (%)
|
Chi-squared (c2)
|
P value
|
1–3 yr
|
4–7 yr
|
8–14 yr
|
|
n = 81
|
n = 501
|
n = 666
|
|
|
D. pteronyssinus
|
23 (28.40%)
|
284 (56.69%)
|
509 (76.43%)
|
101.59
|
<0.01
|
House dust
|
10 (12.35%)
|
79 (15.77%)
|
169 (25.38%)
|
19.75
|
<0.01
|
Mulberry
|
0 (0%)
|
16 (3.19%)
|
17 (2.55%)
|
2.81
|
>0.05
|
Cat dander
|
24 (29.63%)
|
61 (12.18%)
|
56 (8.41%)
|
41.62
|
<0.01
|
Dog hair
|
17 (20.99%)
|
74 (14.77%)
|
83 (12.46%)
|
4.85
|
>0.05
|
Cockroach
|
2 (2.47%)
|
13 (2.59%)
|
32 (4.80%)
|
4.26
|
>0.05
|
Amaranth
|
0(0%)
|
24(4.79%)
|
56(8.41%)
|
12.17
|
<0.01
|
Mold mix
|
11(13.58%)
|
156(31.14%)
|
152(22.82%)
|
16.92
|
<0.01
|
Grass mix
|
1(1.23%)
|
10 (2.00%)
|
20 (3.00%)
|
1.76
|
>0.05
|
Tree pollen mix
|
4 (4.94%)
|
33 (6.59%)
|
36 (5.41%)
|
0.86
|
>0.05
|
Egg
|
34 (41.98%)
|
136 (27.15%)
|
113 (16.97%)
|
35.29
|
<0.01
|
Cow’s milk
|
42 (51.85%)
|
173 (34.53%)
|
162 (24.32%)
|
33.37
|
<0.01
|
Shrimp
|
12 (14.81%)
|
43 (8.58%)
|
57 (8.56%)
|
3.62
|
>0.05
|
Beef
|
12 (14.81%)
|
67 (13.37%)
|
83 (12.46%)
|
0.47
|
>0.05
|
Shellfish
|
6 (7.41%)
|
20 (3.99%)
|
19 (2.85%)
|
4.67
|
>0.05
|
Crab
|
19 (23.46%)
|
68 (13.57%)
|
69 (6.46%)
|
12.21
|
<0.01
|
Mango
|
6 (7.41%)
|
38 (7.58%)
|
43 (6.46%)
|
0.59
|
>0.05
|
Cashew nut
|
39 (48.15%)
|
168 (33.53%)
|
143 (21.47%)
|
37.23
|
<0.01
|
Pineapple
|
1 (1.23%)
|
9 (1.80%)
|
14 (2.10%)
|
0.36
|
>0.05
|
Characteristics of the total serum IgE level distribution
As shown in Table 6, there were 164 children with total IgE < 100 IU/ml, including 96 boys and 68 girls, with the following age distribution: 1–3 yr (n = 16); 4–7 yr (n = 92); and 8–14 yr (n = 56). Total IgE ranged from 100 to 200 IU/ml in 79 patients, including 49 boys and 30 girls, as follows: 1–3 yr (n = 8); 4–7 yr (n = 30); and 8–14 yr (n = 41). A total of 1005 patients were classified in the high-concentration group, including 673 boys and 332 girls: 1–3 yr (n = 57); 4–7 yr (n = 379); and 8–14 yr (n = 569). There was no significant sex difference in total IgE level (c2 = 4.90, P > 0.05), but there was a significant age difference (c2 = 30.69, P < 0.01) and the total IgE level increased with age.
Table 6. Total serum IgE level in different age groups
Total IgE
|
<100 IU∕ml
|
100–200 IU∕ml
|
>200 IU∕ml
|
|
1–3 yr
|
16
|
8
|
57
|
81
|
4–7 yr
|
92
|
30
|
379
|
501
|
8–14 yr
|
56
|
41
|
569
|
666
|
|
164
|
79
|
1005
|
1248
|