Crustacean shellfish allergy is an important cause of food allergy and anaphylaxis in Asia. The major allergen in shellfish allergy is tropomyosin, a pan-allergen that is also found in house dust mites and cockroaches. Tropomyosins from house dust mites (HDMs) have a high sequence homology to shellfish tropomyosins, and cross-reactivity between HDM and shrimp tropomyosins has been demonstrated. Exposure to inhaled tropomyosins from house dust mites has been postulated to be the primary sensitizer for shellfish allergy, in a reaction analogous to the oral allergy (inhalant-food) syndrome. This notion is supported by indirect data from the effects of HDM immunotherapy on shellfish allergy, and strong correlations of shellfish and HDM sensitization. HDM immunotherapy has been reported to induce both shrimp allergy in non-allergic patients and shrimp tolerance in shrimp-allergic patients. Epidemiological surveys have also demonstrated a strong correlation between shellfish and HDM sensitization in both hospital-based and community-based studies. Unexposed populations have also been shown to develop sensitization-shellfish sensitization in orthodox Jews with no history of shellfish consumption was associated with HDM sensitization. Reciprocally, HDM sensitization in an Icelandic population living in a HDM-free environment was associated with shrimp sensitization. In vitro IgE inhibition studies on sera in shrimp-allergic Spanish patients indicate that mites are the primary sensitizer in shrimp-allergic patients living in humid and warm climates. Current data supports the hypothesis that tropomyosin is the link between HDM and shellfish allergies. The role of tropomyosin in HDM and shellfish allergies is a fertile field for investigation as it may provide novel immunotherapeutic strategies for shellfish allergy.
Anaphylaxis ; Asia ; Climate ; Cockroaches ; Dust* ; Food Hypersensitivity ; Humans ; Hypersensitivity ; Iceland ; Immunoglobulin E ; Immunotherapy ; Jews ; Mites ; Pyroglyphidae* ; Sequence Homology ; Shellfish* ; Tropomyosin*

The Health Promotion Board (HPB) has developed the Clinical Practice Guidelines (CPG) on Falls Prevention among Older Adults Living in the Community to provide health professionals in Singapore with recommendations for evidence-based assessments and interventions for falls prevention. This article reproduces the introduction and executive summary of the key recommendations from the HPB-MOH CPG on Falls Prevention among Older Adults Living in the Community for the information of SMJ readers. The chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Health Promotion Board website: http://www.hpb.gov. sg/cpg-falls-prevention. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.
Accidental Falls ; prevention & control ; Aged ; Environment ; Evidence-Based Medicine ; Geriatrics ; standards ; Health Promotion ; methods ; Housing ; Humans ; Incidence ; Middle Aged ; Practice Guidelines as Topic ; Risk Assessment ; methods ; Singapore ; Social Class