ALLERGY AND ITS CAUSES

An allergy is the response of the body’s resistance system to ordinarily harmless substances, such as pollen, foods, dust. Whilst in most people these substances (allergens) cause no problem, in allergic persons their resistance system detects them as a threat and produces an inappropriate reaction. Some people can enjoy walking through a meadow of flowers, while some can’t stand a single rose or some people could finish a bag of nuts while some can barely make it through a single peanut.

Allergies come in many forms, some are seasonal, some throughout the year while some last a lifetime. Symptoms of medicine or drug allergy are minor reactions such as rash, itching, redness, pain, stinging, hives, swelling of lips, tongue or throat, sneezing, runny nose or a serious allergic reaction called anaphylaxis which is indicated by symptoms such as wheezing, shortness of breath, throat and mouth swelling, nausea, vomiting, diarrhea, cramping abdominal pain, fall in blood pressure or even fainting. Some common allergy causing substances are:

Drugs – Nearly any drug can cause an allergy but ones most likely to cause allergies are antibiotics, Aspirin, Insulin, monoclonal antibody therapy, muscle relaxers, nonsteroidal anti-inflammatory, sulfa, chemotherapy, HIV, anti-seizure drugs.

Foods – Common foods causing allergies are milk, eggs, peanuts, tree nuts, soy, wheat, fish.

Insects – Allergies are commonly caused by stinging insects such as bees, wasps, hornets, yellow-jackets, fire ants; biting insects such as kissing bugs, bedbugs, fleas, flies or household pests such as cockroaches and dust mites.

Latex – Contact with everyday products made from natural rubber such as balloons, rubber bands, condoms and diaphragms, rubber household gloves, rubber balls, bandages could cause skin allergies

Mold – Spores of fungi such as mold or mildew also cause allergic reactions

Pets – Allergies to pets with fur such as cats or dogs is common

Pollen – Pollen allergy or hay fever is one of the most seasonal allergies caused by pollens released by trees weeds and grasses.

Allergy issues are widespread and nearly everyone we know would be allergic to a certain substance. If you suspect that you or your loved ones are continuously suffering from an allergic reaction, it is best to approach a clinic offering diagnostic services to rule out serious reactions. An allergy is typically diagnosed in three steps:

Personal and medical history – Detailed medical and personal history will be noted by the doctor to assess the symptoms and their possible causes. Prepare by keeping track of medicines you take, family history and general lifestyle at home, office or school.

Physical examination – Based on the history, if the doctor suspects you have an allergy he will closely examine your eyes, ears, nose, throat, skin and chest. To determine how well your lungs are functioning the doctor may also conduct a pulmonary function diagnostic test or even prescribe an x-ray for the lungs.

Laboratory tests to identify your allergens – For further diagnosis, your doctor may have to do a skin, patch or blood test such as skin prick test, intradermal skin test, specific IgE blood tests, physician-supervised challenge tests. While a laboratory test result is not conclusive of an allergy, it is a rather useful tool in allergy diagnosis.

It is very important to curb allergies at a nascent stage else they could aggravate to serious conditions. If you have the slightest suspicion that you may be suffering from an allergic reaction, consult a specialized diagnostic service like Apollo Diagnostics center at the earliest.

Common Causes of Allergies

  • Exposure to airborne allergens like pollen, mold, dust mites, and pet dander can cause seasonal or year-round allergic reactions, including sneezing, runny nose, and itchy eyes.
  • Certain foods like peanuts, shellfish, dairy, eggs, and wheat can trigger allergic reactions ranging from mild itching to life-threatening anaphylaxis.
  • Bee stings, wasp bites, and other insect venom can cause allergic reactions, leading to swelling, difficulty breathing, or severe anaphylactic shock in sensitive individuals.
  • Some people develop allergic reactions to antibiotics, pain relievers (like aspirin), or even skincare products and detergents, leading to rashes, swelling, or respiratory distress.

 

The Challenges Experiments

Challenge experiments that involve infecting healthy human subjects as a means to test the efficacy of a new vaccine can be invaluable. Great strides in understanding how to treat and prevent such infectious diseases as smallpox, yellow fever, malaria, and influenza have resulted from research involving human beings — both volunteers and those who were “volunteered” to participate. The history of medicine is studded with episodes in which children, men, and women were deliberately infected with pathogens in the hopes of elucidating ways of mitigating, preventing, or curing infections — an approach that continues to be pursued today, as evidenced by the study reported by DeVincenzo et al. in this issue of the Journal (pages 711–722).

Many of the early and most notable challenge experiments involved the scourge of smallpox, a ferocious and often fatal disease. In 1721, Lady Mary Wortley Montagu returned to London from Turkey with the news that variolation — deliberately introducing smallpox pus into the body to produce a milder-than-usual case of smallpox — could also confer lifelong immunity to the disease. After Montagu had her physician variolate her own daughter, she encouraged the royal family to adopt the procedure. In August 1721, physician Charles Maitland received royal permission to undertake a demonstration of variolation at Newgate Prison. Promised pardons, six prisoners underwent variolation in the presence of court physicians. The prisoners survived both the variolations and challenges in the form of subsequent exposures to persons with smallpox. Once Maitland had repeated the experiment in orphans, two princesses were variolated in 1722. These demonstrations did much to spur the adoption of variolation, and in 1757, the variolated included 8-year-old Edward Jenner.

Many physicians are familiar with Jenner’s discovery that protection against smallpox could be conferred by infecting (vaccinating) people with cowpox. After vaccinating the son of his gardener in 1796, Jenner challenged the protection by exposing the boy to smallpox. Jenner’s announcement in 1798 that vaccination conferred immunity to smallpox after first causing a milder infection and without spreading smallpox to others inspired challenge experiments in London, Paris, Vienna, and Boston. At a hospital on one of Boston’s harbor islands, Harvard professor Benjamin Waterhouse vaccinated 19 boys and, 3 months later, inoculated them with smallpox pus; none of them developed the disease. Then he inoculated 2 healthy but unvaccinated boys with smallpox; these 2 boys developed smallpox, but when challenged by exposure to them, none of the vaccinated boys developed the disease. Waterhouse became an uncompromising champion of vaccination — and it is, of course, thanks to widespread vaccination that smallpox has since been eradicated.

Beyond smallpox, the advent of the germ theory of disease fostered a raft of experiments to establish the causative agents of other diseases, and in the absence of animal models, such research often culminated in demonstrations in which disease was induced in healthy human beings by means of a purified culture of the germ in question. Researchers seeking to establish the utility of vaccines for measles, mumps, pertussis, and tuberculosis used challenge experiments to test the degree of protection conferred by each new vaccine.

In some cases, physicians turned to members of their own families to serve as experimental subjects. In the 1930s, for example, pediatricians Hugh and Edith MacDonald injected two of their four sons with the pertussis vaccine. To assess its efficacy, the two then “sprayed whooping cough microbes into the noses of all of them.” The two older boys (called “vaccinated volunteers” by their parents) remained free of whooping cough. The younger children, twin 6-year-old boys, developed severe coughs, paroxysms, and the whoops associated with the disease. Much more frequently, however, researchers in the first half of the 20th century turned to institutionalized children, soldiers, and prisoners as convenient populations for the development and testing of new vaccines and for the study of such infectious diseases as gonorrhea, syphilis, and hepatitis.

Unfortunately, researchers sometimes undertook such efforts with little attention to the ethical concerns raised by purposefully making people sick. In addition to experiments that involved intentionally infecting human subjects with pathogens, experimenters have mounted other “challenge” experiments, including interventions explicitly intended to disrupt normal psychological functioning. Whatever the challenge agent, the intent to create unpleasant symptoms, disease, and discomfort has made challenge experiments a controversial approach to clinical research. One of the challenges for contemporary challenge studies, therefore, is successfully negotiating the balance between the need to advance biomedical understanding and the imperative to respect the welfare and autonomy of participants.

Nearly 50 years ago, in 1966, Henry K. Beecher made an urgent plea in the Journal for serious attention to the increasing number of ethical errors in American clinical research. He outlined 22 “unethical or questionably ethical studies” — including, for example, a clinical experiment of the 1960s in which healthy mentally retarded children at the Willowbrook State School in New York, a chronically underfunded institution with high rates of hepatitis, received intramuscular injections or drank milkshakes containing hepatitis virus so that investigators could monitor the disease in an effort to develop effective means for preventing hepatitis or lessening its severity.

Over the course of the 20th century, as American society gradually expanded the scope of what they considered moral questions, bringing new attention to the rights of children, women, prisoners, and racial and ethnic minority groups, medical researchers similarly sought to protect vulnerable subjects. Beecher’s article helped to prompt federal legislation, the creation of national ethics commissions, and the generation of new guidelines and organizations to protect the rights of research subjects. These included requirements for all prospective studies to undergo review by an institutional review board, requirements for researchers to obtain written informed consent, and special regulations for pediatric research. In the past two decades, concern about healthy volunteers has also occupied federal policymakers. The 2001 death at Johns Hopkins of healthy volunteer Ellen Roche, who had received a challenge agent in an asthma study, and the 1999 death of Jesse Gelsinger at the University of Pennsylvania prompted temporary closures of several research facilities.

Nevertheless, challenge experiments remain an important methodologic approach in the study of such infectious diseases as malaria, cholera, and influenza and in the investigation of such psychiatric disorders as schizophrenia and post-traumatic stress disorder — even as they challenge investigators to provide a compelling rationale for undertaking interventions that intentionally cause disease and discomfort. All experiments involving humans must be thoughtfully planned and carefully evaluated in terms of risk to subjects and the social value of the knowledge to be gained. In addition, the subject selection needs to be equitable, and participants need to be informed and adequately compensated. They must be allowed to withdraw from the study at any time.5 Research involving challenge experiments imposes the same responsibilities on investigators, who must also contend as best they can with the greater visibility that intentional infection brings to biomedical science.

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