Irene Devenney

Skin prick tests may give generalized allergic reactions in infants

BACKGROUND Skin prick testing, a widely used method of studying sensitization, is usually considered quick, pedagogic, and relatively inexpensive. Previous studies have shown very few negative reactions and no fatalities. In contrast, both anaphylaxis and death have been reported as a result of intracutaneous tests. OBJECTIVE To examine detailed case studies of generalized allergic reactions in connection with skin prick testing in order to identify possible risk factors and thereby increase the safety of the test procedure. METHOD A retrospective study of medical records of six cases with generalized allergic reaction occurring during the study period 1996-1998 at the Pediatric Clinic, University Hospital of Linköping, Sweden. Data about the total number of children tested during the period were collected from the clinics database. RESULTS All six cases with generalized reactions were infants <6 months who showed positive skin prick tests to fresh food specimen. Other common features were active eczema and a family history of allergic disease. All infants received prompt treatment and recovered well. The overall rate of generalized reactions was 521 per 100,000 tested children. In the age group <6 months, the corresponding figure was 6,522 per 100,000. CONCLUSION The risk of generalized reactions after skin prick test with fresh food specimens in young children ought to be acknowledged and should lead to increased precautions when performing the test.

High levels of IgG4 antibodies to foods during infancy are associated with tolerance to corresponding foods later in life.

Children with eczema and sensitization to foods are recommended skin care and, if food allergy is proven by challenge, an elimination diet. For most children the diet period is transient, but the process behind tolerance development and the influence of decreased allergen exposure is not fully known. The aim of the study was to investigate the effect of elimination diet on serum and salivary antibodies and to identify immunological parameters related to the ability to tolerate foods. Eighty‐nine children, below 2 yr of age, with eczema and suspected food allergy were included. Recommended treatment was skin care to all children, and 60 children had a period of elimination diet. At 4½ yr of age, the children were divided into two groups, based on if they had been able to introduce the eliminated foods, or not. Serum and salivary antibodies were analyzed with enzyme‐linked immunosorbent assay and UniCAP® before and after a 6‐wk treatment period and at 4½ yr of age. Children sensitized to egg and/or milk that could eat and drink the offending foods at 4½ yr of age, had higher levels of Immunoglobulin G4 antibodies to ovalbumin and β‐lactoglobulin and also higher IgG4/Immunoglobulin E ratios on inclusion in the study, than those who had to eliminate egg and/or milk from their diet, beyond 4½ yr of age. The highest IgG4/IgE ratios were found in children with circulating IgE antibodies to egg and/or milk but negative skin prick test on inclusion. The 6‐wk treatment period did not significantly affect the levels of serum and salivary antibodies. In conclusion, eczematous, food sensitized infants with high levels of IgG4 and high ratios of IgG4/IgE antibodies to food allergens are more likely to consume these foods at 4½ yr than infants with low levels and ratios.

A new model for low-dose food challenge in children with allergy to milk or egg

Background: Atopic eczema and food allergy are common in early childhood. Children seem to gradually develop tolerance to milk and egg, and it is a relief for families when their child can tolerate small amounts of these basic foods, even if larger doses may still cause symptoms. Aim: To develop a model for low‐dose oral food challenge, facilitating re‐/introduction of milk or egg. Methods: In 39 children sensitized to milk and/or egg, we performed 52 challenges using a new standardized model for low‐dose oral food challenge. The recipes were validated for blinding with sensorial tests. Results: Four children challenged to milk had a positive challenge outcome. There were no significant differences with respect to family history, associated atopic manifestations, nutritional supply, eczema severity, or skin‐prick test compared with the non‐reacting children, but total and specific IgE values were significantly higher. All but two of the non‐reacting children were able to introduce milk and egg into their diet without problems.

Skin prick test in duplicate: is it necessary?

BACKGROUND Duplicate skin prick testing has previously been recommended because of reports that accidental negative tests are common. However, duplicate tests also mean an extra allergen load, which may increase the risk of inducing a generalized reaction at the test situation, at least in the youngest infants. OBJECTIVE To investigate whether the occurrence of both a positive and negative test result is a common feature when performing duplicate skin prick tests and can therefore justify the duplicate method. METHODS A retrospective analysis of all skin prick tests performed in duplicate at the pediatric clinic at University Hospital in Linköping, Sweden, in 1997. RESULTS Of 1,087 skin prick tests, 14 resulted in one positive and one negative test, or 1.3%. The corresponding figure in the youngest age group, (ie, <2 years of age) was 3 of 340 (0.9%). CONCLUSIONS Considering the risk of inducing a summation of the reactions, and thereby a generalized allergic reaction, when applying an extra allergen load on the limited surface of the small arm, we conclude that the results of this study justify using single prick test, at least in the youngest age group and probably when testing children of all ages.

Severe Eczema in Infancy Can Predict Asthma Development. A Prospective Study to the Age of 10 Years

Background Children with atopic eczema in infancy often develop allergic rhinoconjunctivitis and asthma, but the term “atopic march” has been questioned as the relations between atopic disorders seem more complicated than one condition progressing into another. Objective In this prospective multicenter study we followed children with eczema from infancy to the age of 10 years focusing on sensitization to allergens, severity of eczema and development of allergic airway symptoms at 4.5 and 10 years of age. Methods On inclusion, 123 children were examined. Hanifin-Rajka criteria and SCORAD index were used to describe the eczema. Episodes of wheezing were registered, skin prick tests and IgE tests were conducted and questionnaires were filled out. Procedures were repeated at 4.5 and 10 years of age with additional examinations for ARC and asthma. Results 94 out of 123 completed the entire study. High SCORAD points on inclusion were correlated with the risk of developing ARC, (B = 9.86, P = 0.01) and asthma, (B = 10.17, P = 0.01). For infants with eczema and wheezing at the first visit, the OR for developing asthma was 4.05(P = 0.01). ARC at 4.5 years of age resulted in an OR of 11.28(P = 0.00) for asthma development at 10 years. Conclusion This study indicates that infant eczema with high SCORAD points is associated with an increased risk of asthma at 10 years of age. Children with eczema and wheezing episodes during infancy are more likely to develop asthma than are infants with eczema alone. Eczema in infancy combined with early onset of ARC seems to indicate a more severe allergic disease, which often leads to asthma development. The progression from eczema in infancy to ARC at an early age and asthma later in childhood shown in this study supports the relevance of the term “atopic march”, at least in more severe allergic disease.

MYCN amplicon junctions as tumor-specific targets for minimal residual disease detection in neuroblastoma

The MYCN gene is frequently amplified in unfavorable neuroblastoma tumors. Therefore, this study aimed at characterizing the novel junctions connecting the amplified DNA segments (amplicons) and obtaining tumor-specific PCR fragments for use in detecting minimal residual disease (MRD). High-density SNP arrays were used to map the end-points of the MYCN amplicons in a subset of neuroblastoma tumors. Primers were designed to give rise to a tumor-specific PCR product and were examined for MRD in the blood and bone marrow using quantitative PCR. Tumor-specific junction fragments were detected in all cases, confirming a head-to-tail tandem orientation of the amplicons and revealing microhomology at the amplicon junctions, thus suggesting a rolling circle caused by microhomology-mediated break-induced replication (MMBIR) as a possible mechanism initiating the MYCN amplification. We also evaluated the use of these junctions as tumor-specific targets for detecting MRD and observed that tumor DNA could be readily detected and quantified in either blood or bone marrow at a sensitivity of 1/106 tumor/control DNA. This study provides new information on the mechanisms of oncogene amplification and envisages means of rapidly obtaining highly sensitive PCR-based tools for tumor/patient-specific monitoring of treatment response and the early detection of relapse in patients with neuroblastoma.

Urinary nitric oxide excretion in infants with eczema

Devenney I, Norrman G, Forslund T, Fälth‐Magnusson K, Sundqvist T. Urinary nitric oxide excretion in infants with eczema.
Pediatr Allergy Immunol 2010: 21: e229–e234.
© 2009 John Wiley & Sons A/S