ABSTRACT
Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK) disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr) as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some serious adverse effects of mosquito coil smoke.
Subject(s)
Animals , Bedbugs , Culicidae , Diptera , Humans , Hypersensitivity/diagnosis , Hypersensitivity/epidemiology , Hypersensitivity/therapy , Insect Bites and Stings/diagnosis , Insect Bites and Stings/epidemiology , Insect Bites and Stings/therapy , Pediculus , Randomized Controlled Trials as Topic/methodsABSTRACT
Objetivos. Establecer si los polimorfismos en la región promotora del gen de la IL-10 localizados en las posiciones -819 y -592 están asociados con la urticaria papular causada por la picadura de pulga, en pacientes pediátricos que asistieron a consulta de alergia o de dermatología a la Fundación Santa Fe de Bogotá, Colombia. Métodos. La frecuencia de estos dos polimorfismos en el ADN fue analizada en 25 niños con urticaria papular y 22 controles por medio de PCR (Polymerase Chain Reaction) y RFLP (Restriction Fragment Length Polymorphisms). Resultados. No hubo diferencias significativas entre las frecuencias alélicas y genotípicas de cada polimorfismo individual o SNP (-819 o -592) entre pacientes y controles (p=0,21, OR=1,87, IC95% 0,79-4,40) cuando fueron calculados por la prueba exacta de Fisher. Conclusiones. Aunque en este trabajo preliminar no se encontró asociación de los polimorfismos reportados en otras poblaciones con la enfermedad alérgica, hay una tendencia en nuestros experimentos a encontrar un mayor número de haplotipos AT en pacientes que en controles Los resultados publicados por nuestro grupo de investigación, en cuanto a que la secreción de IL-10 in vitro se encuentra disminuida en pacientes con urticaria papular y no en controles sanos, indicar ían que la expresión genética de esta citocina estaría alterada en pacientes y, por consiguiente, esta condición estaría exacerbando la enfermedad. Los niveles disminuidos de esta citocina reguladora permitirían el desarrollo de condiciones hiperinmunes, como la alergia y la autoinmunidad...
Objectives: In this study we aimed to establish whether IL-10 promoter region genetic polymorphisms in positions -819 and -592 were associated with papular urticaria caused by flea bite in pediatric patients from the Fundación Santa Fe de Bogotá, Colombia.Methods: The frequency of these DNA polymorphisms was analyzed in 25 infants suffering papular urticaria and 22 healthy controls, after amplification of their corresponding DNA through polymerase chain reaction (PCR) and further analysis of resulting restriction fragment length polymorphisms (RFLP). Results: We found no significant differences in allelic and genotypic frequencies of either -819 or -592 SNPs between patients and healthy controls (p=0.21, OR=1.87, 95% IC=0.79-4.40). Conclusions: Although we did not find in this preliminary study a genetic association between papular urticaria and previously reported allergyassociated SNPs such as -819 and -592, we found higher numbers of allergy-associated AT haplotypes in patients than in controls. Previously published results from our group showed in vitro a diminished IL-10 secretion in patients and not in healthy controls. This finding, together with our present results, would indicate that the genetic expression of this cytokine could be altered in patients and that this condition could determine the exacerbation of papular urticaria. Low levels of this cytokine would allow for the development of hyperimmune conditions such as allergy and autoimmunity...
Subject(s)
Cytokines , Urticaria , HypersensitivityABSTRACT
Objective To investigate the etiology of papular urticaria: is it caused only by arthropod-like insects-bite allergy, or by multiple factors such as food allergy, disturbance of gastrointestinal function and infection? Methods We searched, by computer and manually, the foreign and domestic literature related to the etiology of papular urticaria published since 1950s, and according to the methods of evidence-based medicine, systematically evaluated the evidence supporting either the insect-bite theory or the multiple factor theory. Results Twenty-nine articles ( 22 English and 7 Chinese ) supported the theory of hypersensitivity to bites from certain insects such as mosquitoes, gnats, fleas, mites, bedbugs etc. Two articles in Chinese mentioned the possibilities other than insect-bite, but the reliability was unconvincing, because the authors did not present the source of data or statistical methods used in the articles. The evidence from epidemiology, histopathology, laboratory and clinical researches all supported the insects-bite theory. No proven evidence was found supporting other aetiological hypotheses. Conclusion Our results suggest that papular urticaria is caused only by the allergy to stings or bites of arthropods, and other hypotheses still lack convincing evidence.