Monday, February 4, 2008

Allergy

An allergy refers to an exaggerated reaction by our immune system in response to bodily contact with certain foreign substances. It is exaggerated because these foreign substances are usually seen by the body as harmless and no response occurs in non- allergic people. Allergic people's bodies recognize the foreign substance and one part of the immune system is turned on.
Allergy-producing substances are called "allergens." Examples of allergens include pollens, dust mite, molds, danders, and foods. To understand the language of allergy it is important to remember that allergens are substances that are foreign to the body and can cause an allergic reaction in certain people.

When an allergen comes in contact with the body, it causes the immune system to develop an allergic reaction in persons who are allergic to it. When you inappropriately react to allergens that are normally harmless to other people, you are having an allergic reaction and can be referred to as allergic or atopic. Therefore, people who are prone to allergies are said to be allergic or "atopic."

Austrian pediatrician Clemens Pirquet (1874-1929) first used the term allergy. He referred to both immunity that was beneficial and to the harmful hypersensitivity as "allergy." The word allergy is derived from the Greek words "allos," meaning different or changed and "ergos," meaning work or action. Allergy roughly refers to an "altered reaction." The word allergy was first used in 1905 to describe the adverse reactions of children who were given repeated shots of horse serum to fight infection. The following year, the term allergy was proposed to explain this unexpected "changed reactivity."

Friday, January 25, 2008

Allergies blamed for some cases of irritable bowel

People with allergies appear to be more likely to have irritable bowel syndrome (IBS) than do those without allergies, suggesting that the conditions may be linked in some instance, Chicago-based researchers report.

Lead investigator Dr. Mary C. Tobin told Reuters Health that "the real hope of this study is that patients and physicians recognize the association between allergies and IBS."

People with IBS suffer chronic discomfort with cramping, diarrhea or constipation. The causes of IBS are unclear and there has been debate whether it is mostly due to psychological factors or biological triggers, or perhaps a combination.

To investigate a possible connection with allergies, Tobin and her colleagues at Rush University Medical Center surveyed 125 patients: 39 were attending an allergy clinic, 36 were attending a gastroenterology clinic, and the remaining 50 were being seen at a general medicine clinic.

IBS was present in 44 percent of the patients attending the allergy clinic, similar to the rate among patients at the gastroenterology clinic (39 percent) and significantly greater than the 20 percent rate seen among general clinic attendees.

Overall, patients reporting allergic conditions such as hay fever, eczema, and asthma were three times more likely than other patients to have IBS, the investigators report in the Annals of Allergy, Asthma and Immunology.

Given these findings, the researchers suggest that patients who have typical IBS symptoms plus signs of allergies should be considered as a separate subgroup of IBS patients.

Tobin added that "identifying the allergic triggers, both inhaled and ingested, as well as appropriate treatment of the allergies, can markedly improve the patient's quality of life by controlling the symptoms."