|
Home / Health
The Cause Of Hypersensitivity Reactions And Allergy
By:Alisha Dhamani
Millions of Canadians suffer from allergies and asthma. When your immune system identifies a normally harmless material as a threat, it can set off symptoms like sniffles, sneezes, rashes or breathing problems.
Although allergies and colds have similar symptoms, there are some telltale signs that can help you differentiate between them. If you aren't sure whether you have allergies or just a cold, ask your health professional. Your pharmacist or doctor can help determine the cause of your symptoms and recommend appropriate treatment.
Experts think that 1-2 percent of Canadians have serious allergies to food, insects, medications, latex, and exercise. These allergies are potentially life-threatening emergencies that require immediate medical attention.
A person experiencing a serious allergic reaction may have difficulty breathing, throat swelling, skin redness or itching, and an irregular heartbeat or palpitations. In most cases, it is recommended that people with an identified serious allergy wear a MedicAlert bracelet and carry an EpiPen, which is an injection device that contains epinephrine.
A recent study showed that two out of three parents were unsure of how to use their child's EpiPen, and almost half did not even carry their EpiPen with them at all times. If you or a family member have a serious allergy, talk to your pharmacist or doctor, and make sure you know how to recognize all the signs of a potentially life-threatening reaction so that you know exactly what to do if the time ever comes.
Delayed hypersensitivity reactions are inflammatory reactions initiated by mononuclear leukocytes. The term delayed is used to differentiate a secondary cellular response, which appears 48-72 hours after antigen exposure, from an immediate hypersensitivity response, which generally appears within 12 minutes of an antigen challenge. These reactions are mediated by T cells and monocytes/macrophages rather than by antibodies. They are also termed type IV hypersensitivity reactions.
Delayed hypersensitivity is a major mechanism of defense against various intracellular pathogens, including mycobacteria, fungi, and certain parasites, and it occurs in transplant rejection and tumor immunity. The central role of CD4+ T cells in delayed hypersensitivity manifests in patients with AIDS. Because of the loss of CD4+ cells, the host response against intracellular pathogens such as Mycobacterium tuberculosis is markedly impaired. The bacteria are engulfed by macrophages but are not killed.
If T-cell function is abnormal, the patient presents with opportunistic infections, including infection with mycobacteria, fungi, parasites, and, often, mucocutaneous candidiasis. Undesirable consequences of delayed-type hypersensitivity (DTH) reactions include illness such as contact dermatitis and allograft rejection.
Examples of DTH reactions are contact dermatitis (eg, poison ivy rash), tuberculin skin test reactions, granulomatous inflammation (eg, sarcoidosis, Crohn disease), allograft rejection, graft versus host disease, and autoimmune hypersensitivity reactions. Of note, the Rhus genus of plants, which includes poison ivy, poison oak, and poison sumac, all cause identical rashes.
The cellular events that result in delayed hypersensitivity reactions primarily involve T cells and macrophages. First, local immune and inflammatory responses at the site of foreign antigen up-regulate endothelial cell adhesion molecule expression, promoting the accumulation of leukocytes at the tissue site. The antigen is engulfed by macrophages and monocytes and is presented to a T cell that has a specific receptor for that antigen. Macrophages secrete interleukin (IL)1, IL-2, IL-6, and other lymphokines. Cytotoxic T cells can also be activated. The recruited macrophages can form giant cells. The characteristic histologic appearance of the macrophage T-cell infiltrate is a granuloma. This type of infiltrate in the tissue is called granulomatous inflammation.
Several variants of DTH exist, and their precise pathophysiologic mechanisms are slightly different. For example, in contact hypersensitivity reactions, the epidermis is involved; in pulmonary tuberculosis (TB), lung tissue is involved.
Delayed hypersensitivity reactions are normal physiological events. Anything that alters these normal events can lead to multiple opportunistic infections. Immune deficiencies (congenital or acquired) and immunosuppressive agents can alter this normal response.
he cellular events that result in delayed hypersensitivity reactions primarily involve T cells and macrophages. First, local immune and inflammatory responses at the site of foreign antigen up-regulate endothelial cell adhesion molecule expression, promoting the accumulation of leukocytes at the tissue site. The antigen is engulfed by macrophages and monocytes and is presented to a T cell that has a specific receptor for that antigen.
Macrophages secrete IL-1, IL-2, IL-6, and other lymphokines. Cytotoxic T cells can also be activated. The recruited macrophages can form giant cells. The characteristic histologic appearance of the macrophage T-cell infiltrate is a granuloma. This type of infiltrate in the tissue is called granulomatous inflammation.
Digg
del.icio.us
Blink
Stumble
Spurl
Reddit
Netscape
Furl
Article keywords: allergy, reactions, health, disease, asthma, medicine
Article Source: http://www.articles2k.com
Jigfo.com is a global platform for sharing and learning knowledge. For more information on this article topics visit:
http://www.jigfo.com
http://homeopathy.jigfo.com/
http://herbalism.jigfo.com/
http://pamelareed.jigfo.com/
http://chiropractic.jigfo.com/
|
|
| Top Health Articles |
- 1). Collarbone Injury By : Frank Vanderlugt
The clavicle or “collar bone” connects the scapula bone in the shoulder to the sternum in your chest. It functions to hold the shoulder upward and backward.
Clavicle fractures are common bone injuries. A break in the clavicle bone is usually a closed fracture that normally takes approximately 6 weeks to heal in an adult, 4 weeks in a child. The injury rarely requires surgery.
|
- 2). The Hottest Hair Trends And The Sexiest Hairstyles For 2007 By :
Copyright 2006 David Maillie
Hair has become unequivocally important as it can literally make one look like a movie star or a has been from Hee Haw, which died out many years ago. It is big enough that it is a multi billion dollar industry and the average bill in a salon is approaching $100. In the big cities with a hot hairstylist like Jonathon in Beverly Hills prices can easily top $500 for a cut and style.
|
- 3). Muscle Imbalance And Chronic Injuries By : Jeff P. Anliker, LMT
Injuries can occur anywhere and at anytime, but the most prevalent place of occurrence is in the workplace. The reason for such a high rate of injury is that people spend 8-18 hours a day, 5-7 days a week performing unidirectional (one-way) movement patterns, causing an imbalance in the musculoskeletal system that results in the overuse and under use of certain muscle groups.
|
- 4). Why Whey Protein? By : Sandy Knoll
With all of the recent negative press given to body supplements, it makes good sense to be cautions about using different nutritional supplements as a part of your body building efforts.
Whey protein has been lauded as a safe, natural and simple supplement. It's use has become popular for those genuinely interested in good health through physical fitness and body building.
|
- 5). Autism and its Generated Behavioral and Mental Impairments By : Groshan Fabiola
Autism is a complex neurological disorder that dramatically affects people’s behaviors and social interactions. The disorder can be revealed in early childhood, by the age of 3. Although the first signs of autism can sometimes be identified in infants, the disorder is usually discovered at a later stage of life. Autistic children present a wide range of behavioral abnormalities, and they can be easily identified among normal children.
|
- 6). Why Asbestos Cancer Affects More Men? By : Alfred J.James
Who needs to be examined?
Individuals who have been exposed (or suspect they have been exposed) to asbestos fibers on the job or at home via a family contact should inform their physician of their exposure history and any symptoms. Asbestos fibers can be measured in urine, feces, mucus, or material rinsed out of the lungs.
A thorough physical examination, including a chest x-ray and lung function tests, may be recommended.
|
- 7). The Benefits of Martial Arts Training By : Clint Leung
As any martial arts practitioner will tell you, there are multiple benefits in martial arts training. Of course, the most obvious benefit is a knowledge of self defense which is one of the major reasons why the martial arts were developed in the first place. Knowing how to defend oneself and loved ones in a potentially dangerous situation is an asset in today’s world just as it was hundreds of years ago.
|
- 8). Study Says Obesity May Be Caused By Virus By : Rick Hendershot
In new study published this month, a research team claims to have found evidence that a contagious virus can contribute to obesity.
The team found that a specific human adenovirus Ad-37 seems to trigger obesity in chickens. Previous studies had linked other adenoviruses -- Ad-36 and Ad-5 -- to obesity in animals.
These and other adenoviruses cause colds and other common illnesses in people.
|
- 9). How Long Will It Take To Gain Muscles| Build Muscle Mass By : Chris Chew
There are many factors to consider when you want to know how long will it take for you to gain and build muscle mass. Questions like are you eating enough and the right nutrients to accelerate muscle growth, are you exercising correctly and regularly and do you have the genes for quick muscle growth need to be addressed.
In this article, we shall discuss whether you have the genetic make up to gain and build muscles quickly.
|
- 10). Breathe Easy: Some Asthma Relief Tips By : Nick Carter
Asthma is the seventh-ranked chronic health condition in the United States and the leading chronic illness of children. It is a chronic inflammatory disease that makes airways (bronchial tubes) particularly sensitive to irritants.
During an asthma attack, tightening of the smooth muscles around the bronchial tubes causes them to become inflamed, narrow inside, and produce excess mucus.
|
| New Health Articles |
- 1). How To Break An Addiction By : John Morris
You need to evaluate the problem and find what triggers your addicts and what specific need it is using. Once you have determined that, you can begin breaking yourself of the habit one step at a time...
|
|
|
|
|
|
|
- 5). Make Your Heart More Healthy By : Dan Sherman
Does it seem like there are more health risks these days than there were in the past? Well, the plain and simple truth is, there are. Now, more than ever, people around the globe grapple with various heath afflictions.
|
- 6). The Best Ways To Quit Cigarette Smoking By : Jonty Smith
The author packed in his 40-a-day habit within a few hours. He did it quickly, easily and painlessly. Why then do so many other smokers struggle to quit? In this article, the author explains the best ways to quit cigarette smoking, and why many of the established methods are counter-productive.
|
- 7). Can Chocolate Really Kill Your Dog By : Gregg Hall
We have all heard this all of our lives but how big a threat is it really? Is it life threatening or will it just make him sick? How much chocolate does the animal have to eat for it to cause a negative reaction?
|
- 8). The Attraction Of Magnetic Therapy By : John Morris
Magnetic therapy is an alternative treatment for common ailments. The most commonly treated ailments for that magnetic therapy is used for are arthritis, pain, inflammation, muscle tension, migraines, tumors, asthma, allergies, diabetes and many other joints or healing complaints...
|
|
|
|
|
|
|
