Latex as found in nature is a milky sap-like fluid found in 10% of all flowering plants [
Latex sensitization is defined as the presence of immunoglobulin antibodies to NRL products without clinical manifestations [
The association of latex allergy and allergy to plant-derived foods is called latex-fruit syndrome and is attributed to the cross-reactivity between the major latex allergen hevein and hevein-like domains (HLDs) from fruit class 1 [
This study comprised 400 allergic infants and children enrolled consecutively from the Pediatric Allergy and Immunology Clinic, Children’s Hospital, Ain Shams University, and the outpatient clinics of El-Mounira and El-Zawya hospitals over the period from March 2011 to June 2013. Patients included suffered clinical allergic disorders including bronchial asthma (BA), skin allergy, and allergic rhinitis (AR). An informed consent was obtained from the parents and caregivers prior to enrollment. Approval of the local ethics committee was obtained.
The diagnosis of BA was established according to the criteria of the American Thoracic Society [
All patients included in the study were subjected to the following.
SPSS for Windows, release 15.0 (SPSS Inc., USA), was used for data entry and analysis. All numeric variables were expressed as mean ± standard deviation (SD) or median (interquartile range (IQR)) as appropriate. Comparison of continuous variables was done using Student’s
The study sample comprised 212 males (53%) and 188 females (47%) (Table
Demographic and clinical data of patients.
Parameter | Positive latex SPT |
Negative latex SPT |
|
|
---|---|---|---|---|
Sex | Male | 8 (2%) | 204 (51%) | 0.806 |
Female | 8 (2%) | 180 (45%) | ||
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Age (years) | Range | 1–17 | 0.5–15 | 0.338 |
Median | 5.2 | 4.5 | ||
Interquartile range (IQR) | 9.7 | 4 | ||
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Duration of exclusive breast feeding (months) | Mean | 5.33 | 5.7 | 0.257 |
SD | 1.29 | 1.4 | ||
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Site of allergy | Respiratory allergy only (BA, AR, or both) | 9 (2.25%) | 273 (68.25%) | 0.334 |
Skin allergy only | 3 (0.75%) | 61 (15.25%) | ||
Both respiratory and skin | 4 (1%) | 50 (12.5%) | ||
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Diagnosis | All BA cases | 11 (2.75%) | 315 (78.75%) | 0.18 |
All AR cases | 2 (0.5%) | 42 (10.5%) | 0.845 | |
All skin allergy cases | 7 (1.75%) | 111 (27.75%) | 0.202 | |
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Duration of illness (years) | Median (IQR) | 3.25 (3) | 2.5 (4) | 0.251 |
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History of latex allergy | 7 (1.75%) | 2 (0.5%) | 0.000 | |
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Exposure to latex gloves | 8 (2%) | 97 (24.25%) | 0.104 | |
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Positive family history of allergy | 11 (2.75%) | 258 (64.5%) | 0.896 | |
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Fruit allergy | 7 (1.75%) | 218 (54.5%) | 0.304 | |
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Absolute eosinophilic count ×103/Cu·mm | Median | 0.2 | 0.2 | 0.928 |
IQR | 0.27 | 0.3 | ||
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IgE% of normal for age | Median | 96.3 | 66.67 | 0.477 |
IQR | 133.3 | 105.53 |
BA: bronchial asthma.
AR: allergic rhinitis.
History of exposure to balloons and rubber toys was positive in 358 (89.5%) patients, to latex bottle nipples in 166 (41.5%), to erasers in 203 (50.7%), and to latex gloves in 105 (26.2%). A history of allergy to fruits, namely, banana, kiwi, and pears, was found in 225 patients (56.25%). The presence of risk factors such as neural tube defect and urogenital anomalies with repeated urinary catheterization was found in 3 (0.75%) and hand dermatitis in 6 (1.5%).
The result was positive in 16/400 patients (4% of the studied sample). Seven of our patients (1.75%) had positive latex allergy; that is, they had positive history of allergy to latex products concomitant with positive latex SPT (Figure
Latex sensitivity and SPT results.
Positive history of latex allergy was significantly higher among patients with positive latex SPT having a frequency of 77.8% in comparison to 22.2% in those with negative latex SPT. The odds ratio (OR) was 148 (confidence interval: 27-817). Allergy to fruits was present in 7/16 (43.7%) of the patients who reacted positively to latex SPT versus 218/384 (56.7%) of those with negative result (OR (CI): 0.592 (0.216–1.62); insignificant).
Positive SPT to latex was observed in only 3.2% (9/282) of patients with isolated respiratory allergy and 4.7% (3/64) of patients with isolated skin allergy in contrast to 7.4% (4/54) of patients with concomitant respiratory and skin allergy (
Positive SPT to latex was seen in 3.4% (11/326) of all patients with bronchial asthma, 5.9% (7/118) of patients with skin allergy (all the 7 had urticaria), and 4.5% (2/44) of patients with AR (OR (CI): 0.48 (0.16–1.4); 1.9 (0.6–5.2); 1.16 (0.25–5.2), resp.).
The patient’s age, duration of exclusive breast feeding, age of weaning, duration of the allergic disease, absolute eosinophilic count, total serum IgE, and IgE percent did not bear a statistically significant relation with positivity of latex SPT (
The sensitivity of latex SPT was 77.77% and specificity was 97.69% with positive predictive value of 43.75% and negative predictive value of 99.47% with an overall efficacy of 97.25%.
Immediate hypersensitivity to natural rubber latex has increased since the early 1980s. High prevalence of latex sensitization and allergy are observed among health care workers, atopic individuals, and children who are exposed to multiple surgical maneuvers such as spina bifida and urogenital anomalies [
In children, latex sensitization prevalence studies are scarce and involve different population sampling and allergy testing methods, which makes it difficult to compare across studies. Aiming at determining the brunt of the problem in allergic children and its relation to positive history as reported by the patients or their caregivers, we studied the prevalence of latex sensitization in a sample of allergic Egyptian children. This might help in deciding the need for measures to reduce the problem.
In the present study, latex SPT revealed that 4% of the studied sample (16/400) was sensitized to latex. There are no reports on the size of the latex sensitization problem in Egypt. A positive history of exposure to latex products was highly encountered in our cohort of allergic children reaching as high as 89.5% for balloons and rubber toys and 26.2% for latex gloves. Latex containing products such as toys, bottle nipples, and erasers are widely used in Egypt. It is to be noted that most hospitals in Egypt are still using latex-containing medical gloves. However, few dentists and physicians became aware of this problem and started introduction of latex-free medical gloves in their private clinics. Moreover, latex allergens present in sediment and airborne particulate material, derived from tire debris due to heavy urban vehicle traffic and from latex industries in our country (such as latex paints, mattresses, and medical instruments), could be important factors in producing latex sensitization. In a study of 326 atopic children, 10 (3%) presented positive skin test to latex, but only five (1.5%) also had a positive clinical history to latex exposure [
Meglio and associates [
The corresponding percentage in the general pediatric population is 0.3–4% as reported by some authors [
In the present study, 7/16 of those with positive latex SPT gave positive history of allergy to latex. This was a significant finding as compared to those with negative SPT, with a high odds ratio OR (CI): 148 (27–817). The latex SPT was specific rather than sensitive (97.6% versus 77.7%) and showed a high negative predictive value of 99.47%. In an earlier study, the sensitivity of latex SPT was 100% and the specificity was 98% [
The frequency of latex sensitization in all our asthmatic patients was 3.4% (11/326). In a sample of 1097 patients with occupational asthma, 4.9% were found sensitized to latex [
In our series, 2/44 (4.5%) AR patients had positive latex SPT. In comparison, Airaksinen and colleagues [
Our study population included 118 patients with skin allergy (+/− other allergic diseases) where 7 of them (5.9%) had positive SPT to latex. The incidence of latex allergy among 844 patients under 14 years of age with skin allergy in 2001/2002/2003 was 6.1/11.3/15.9%, respectively, denoting a steady rise [
The coexistence of more than one allergic disease in the same patient might increase the possibility of having latex hypersensitivity based on the finding in the present work that 7.4% (4/54) of patients with both respiratory and skin allergy had positive latex SPT in contrast to only 3.2% of patients with respiratory allergy and 4.7% of those with skin allergy.
Our study population included 3 patients with neural tube defects and urogenital anomalies necessitating frequent exposure to latex made catheters. Latex skin prick test was positive in one (25%). Spartà and associates [
In the present study, half of all allergic children had history of fruit allergy (43.7% of patients with positive and 56.7% of those with negative latex SPT). Only 6 out of 222 patients with history of banana allergy (2.7%) had positive latex SPT and only 2/6 had positive history of latex allergy. The only patient who had history of kiwi allergy had positive latex SPT and denied history of latex allergy. Overall, the difference was insignificant (OR (CI): 0.59 (0.2–1.62)) perhaps indicating that history of fruit allergy should be confirmed by SPT or oral challenge before considering it as a risk factor for latex allergy. Other fruits that cross-react with latex such as avocado are not popular in Egypt. Radauer et al. [
It is concluded that latex skin sensitization was found in 4% of the studied allergic children, yet latex allergy as determined by a positive self/parental report and positive skin prick test was observed in only 1.75%. Although underrecognized, latex is an important allergen in the pediatric age group. It was observed to be especially associated with multiple allergic diseases coexisting in the same patient. Pediatric allergologists should educate their patients on latex allergy and encourage the use of latex-free products. Studies on the prevalence of latex sensitization in the general population as well as studies on environmental air pollution with latex are recommended.
The authors declare that there is no conflict of interests regarding the publication of this paper.