|
This Month³s Feature Review:
Is it Anaphylaxis?
With the increased prevalence and awareness of Allergies, an increasing number of patients will be presenting to their emergency doctors with what looks like anaphylaxis. The emergency doctor knows that he / she could be dealing with a life-threatening situation and has to make quick decisions. Often Adrenaline is given at the time, and the patient is then left with the fear of this situation recurring.
It is therefore very important for the diagnosis of Anaphylaxis not to be taken lightly, both for the immediate management of the patient and the long-term implications.
It is also more likely that an atopic patient who has had 1 anaphylactic reaction will develop ?€benign" acute urticaria (hives), from eating strawberries say, and will panic and develop ?€difficulty breathing" due to hyperventilation. At 1am when this patient presents to an unknown doctor, it would be difficult to withhold adrenaline. This is one reason why a good history and objectivity should prevail.Then there are the patients who have never had a true anaphylactic reaction, but have had several episodes or recurrent acute generalized urticaria with angioedema (swelling) of the face associated with several subjective symptoms that make the diagnosis of anaphylaxis possible. Oftentimes these patients are labelled as ?€Anaphylactic" and given an Epi-pen. It then becomes very difficult to remove that label and the associated fear.
Click here for full Article
Allergic sensitisation owing to second-hand cat exposure in schools
B.R. Ritz et al, Dept Epidemiology, UCLA, LA & Institute of Epidemiology, Neuherberg, Germany
Background: Environmental allergen loads play an important role in triggering symptoms in atopic individuals. While a number of previous studies have shown that cat allergens (Fel d 1) can be found in school dust samples, no study has provided evidence that public places contribute to increased atopic sensitisation rates in children.
Methods: we employed data collected in a health survey of school children living in Germany in order to examine the association between the proportion of class and schoolmates reporting cat contact and sensitisation rates in children.
Results: Among 1893 children, 8.7% were sensitised to cats. Those sensitised were 5-7 times more likely to have received an asthma diagnosis or to have reported wheezing. Pupils without regular contact with cats were twice as likely to test positive for major cat allergen when the proportion of schoolmates with cat contact was high. No such relation was observed amongst children reporting regular cat contact.
Conclusions: Our study suggests that cat allergens in school environments contribute to allergic sensitisation and atopic diseases such as asthma. Thus, asthma methods reduce the allergen load in classrooms should be considered.
Reference: Allergy 2002; 57:357-361
Breast-feeding duration is a risk factor for atopic eczema
R.L. Bergmann, U Wahn and the MAS study group, Germany
Background: The results of numerous studies on the influence of breast-feeding in the prevention of atopic disorders are often contradictory. One of the most important problems is confounding by other lifestyle factors.
Objective: The aim of the present study was to analyse the effect of any breast-feeding duration on the prevalence of atopic eczema in the first seven years of life, taking into account other risk factors.
Methods: In an observational birth cohort study 1314 infants born in 1990 were followed for seven years. At 3, 6, 12, 18, 24 months and every year thereafter, parents were interviewed and filled in questionnaires, children were examined and blood was taken for in vitro allergy tests. Generalized Estimation Equations (GEE) models were used to model risk factors for the prevalence of atopic eczema and for confounder adjustment.
Result: Breast-feeding was carried out for longer if at least one parent had eczema, the mother was older, did not smoke in pregnancy, and the family had a high social status. The prevalence of atopic eczema in the first seven years increased with each year of age OR 1.05; 95 CI 1.01-1.09 for each year), with each additional month of breast-feeding (1.03; 1.00-1.06 for each additional month), with a history of parental atopic eczema (2.06; 1.38-3.08), and if other atopic signs and symptoms appeared, especially specific sensitisation (1.53; 1.25-1.88), and asthma (1.41; 1.07-1.85). Although breast-feeding should be recommended to all infants, it does not prevent eczema in children with a genetic risk.
Conclusions: Parental eczema is the major risk factor for eczema. But in this study, each month of breast-feeding also increased the risk.
Reference: Clinical & Experimental Allergy, Volume 32, Issue 2 Page 205 ?• February 2002
Anaphylaxis to riboflavin (vitamin B2)
Liang-Shiou Ou et al, Dept Paediatrics, Chang Gung Childrens Hospital, Taiwan
Background: Vitamin supplements are used more commonly in normal healthy subjects than in patients with vitamin deficiency. Thiamine (vitamin B1) is the vitamin that most frequently induces allergic reactions. To the best of our knowledge, no case of anaphylaxis to riboflavin has thus far been reported in the literature.
Objective: we describe a previously healthy 15-year-old boy in whom anaphylaxis developed several times after he drank 1 soft drink or took a single multivitamin tablet. This study was done to determine which of the many components found in the soft drink and multivitamin tablet caused the anaphylactic reaction.
Methods: In an outpatient clinic the availability of complete resuscitative procedures, we performed single blind skin prick test and intradermal skin tests on the patient with various pure vitamin components of the soft drink and the multivitamin tablet. Physiologic saline and histamine were used for negative and positive controls, respectively.
Results: Riboflavin, a component of both the soft drink and the vitamin tablet, produced positive reactions on intradermal skin tests in the patient. Positive reactions were not present in the normal control subjects.
Conclusions: Riboflavin is a previously unreported cause of anaphylaxis. Free-form riboflavin may potentially be associated with an anaphylactic reaction. It is vitamin widely used in many patients with chronic disease and in healthy subjects. Vitamin B2 must be considered as a cause of anaphylaxis.
Reference: Ann Allergy Asthma Immunol 2001;87:430-433
A lower prevalence of atopy symptoms in children with Type 1 diabetes mellitus
R Meerwaldt et al, Holland
Background: The Th1 / Th2 concept is a model to understand the pathophysiology of certain diseases. Atopic diseases (asthma, eczema and hay fever) are characterised by a chronic inflammatory reaction that is dominated by Th2 cells, and Type 1 diabetes mellitus (DM) is Th1-cell dominated. Because it is known that Th1 and Th2 cells reciprocally counteract each other, it can be speculated that the prevalence of Th2-mediated disease is lower in patients with Th1-mediated disease.
Objective: To compare the prevalence of atopic diseases between children with DM and age matched controls.
Methods: Parents of children with DM were requested by Dutch Paediatricians to complete the international Study of Asthma and Allergies in Childhood (ISAAC) questionnaire on the prevalence of atopic diseases. A control group was derived from a Dutch cross-sectional survey (the ISAAC2 study).
Results: We received 555 completed questionnaires, which is estimated to be 25 of the total number of Dutch children with DM. The control group consisted of 777 children. After age matching, the questionnaires of 188 DM patients were used. Symptoms of asthma, hay fever and eczema were reported less in the group of children with DM compared with the control group (wheeze last year, OR 0.796, 95 CI 0.408-1.554; hay fever symptoms last year, OR 0.642, 95 CI 0.369-1.118; eczema symptoms last year, OR 0.693, 95 CI 0.430-1.115).
Conclusions: The lower prevalence of asthma, hay fever and eczema symptoms in DM patients compared with age-matched controls, although not statistically significant, is consistent with the TH1 / Th2 concept.
Idiopathic anaphylaxis: a descriptive study of 81 patients in Spain
Miguel A. Tejedor Alonso, et al, General Hospital of Albacete, Spain
Background: Few European groups have published data on series of patients with idiopathic anaphylaxis.
Objective: Our aim was to report on our experience with this entity in Spain.
Methods: We conducted a two-part investigation. The first part was a descriptive cross-sectional study of 81 patients with idiopathic anaphylaxis, diagnosed between January 1990 and December 1995 in the Allergy Unit of The General Hospital of Albacete, Spain. The second prong was a prospective, longitudinal study that evaluated the activity of the condition.
Results: Female patients constituted 68% of the study group with idiopathic anaphylaxis; the mean age of the 81 patients was 30.0 +/- 17.3 years. The number of episodes of idiopathic anaphylaxis during the year of greatest frequency varied widely (median, 2; range, 1 to 130). The duration also varied considerably, with a range of 0.03 to 300 months (median, 2 years). Most patients entered the study in remission, and 93% of these patients remained in remission throughout the follow-up period. Only 9% of the patients had cardio-vascular involvement.
Our series of patients with idiopathic anaphylaxis had a notable prevalence of atopic diseases (48%), food allergy (20%), and episodes of anaphylaxis with an identifiable cause (15%), In addition, a high frequency (58%) of idiopathic urticaria was noted; the urticaria was acute in 62% of the affected patients.
Conclusions: Our series of patients with idiopathic anaphylaxis is similar to previously published series.
Reference: Annals of Allergy, Asthma, and Immunology 2002; 88:313-318
Episodic stridor with latex nipple use in a 2-month-old infant
Freishtat RJ, Goepp JG, Dept. Paediatrics, Strong Memorial Hospital, Univ of Rochester School of Medicine, Rochester, NY
Latex allergy in the Paediatric population is most commonly identified in patients who have undergone multiple operations for neural tube defects or genitourinary anomalies.
However, there are a significant number of children who, without usual risk factors, clinically and/or serologically appear to be latex allergic. There is sporadic information in the medical literature regarding reactions to latex allergens in household items, especially in patients younger than 1 year old. Several recent reports even support the existence of reactions to latex pacifiers. We report a case of an atopic 2-month-old infant who experienced the previously unreported reaction of repeated stridor on exposure to latex nipple while feeding. It is important that clinicians recognize stridor as a potential reaction to latex in infants.
Reference: Ann Emerg Med 2002 Apr;39(4):441-3
|
