toxicity - pesticides, herbicides and insecticides - Blackherbals.com

Continued from page 28 - Allergy and Pesticidesairway); infections, allergens, and irritants (includingchemicals) trigger excessive spasm and swelling of thebronchi. Once recognized, reactive airway patients can behelped with a lifelong medical program and strictavoidance of specific triggering substances. Extrinsicasthma refers to a respiratory reaction to specificallergens in the environment. Environmental allergensmay include manmade substances such as chemicals andnatural substances such as airborne mold from peanuts orcheese. There are allergic reactions to microbes, dander,insect venoms, house dust, and plant products such aspollens, wood dust, thorns and sap. Allergic responses toprescribed drugs are well known. Many causes ofextrinsic asthma can be diagnosed with skin tests and canbe corrected or modified by a series of shots calleddesensitization.WHAT ABOUT ALLERGY OF THE SKIN?There are at least five major types of skin reactions. Themost common is an irritant reaction from a sharp prick orscratch. This will cause an immediate flare of the skinespecially in certain atopic individuals. The next type is areaction to a foreign protein which produces a hive orwelt which itches. This occurs within 30 minutes througha substance carried in the blood called IgE(immunoglobulin). The third response is delayedhypersensitivity which is characterized by a response ofthe lymphocytes or white blood cells. This response takesa minimum of 24 to 36 hours to respond to the allergicchallenge of the sensitizing substance. The fourth type ofresponse is similar to the third type but requires additionof ultraviolet light and is called photosensitivity. Forexample, oral tetracycline antibiotic can cause a delayedtype of rash in people when they are exposed to sunlight.It is more severe and long lasting than simple sunburn.The fifth type of skin reaction is poorly understood. Thisis a psychosomatic skin reaction that occurs when aperson, under unusual stress, breaks out in hives.HOW ARE PEOPLE EXPOSED TO PESTICIDESWHICH MIGHT RESULT IN ALLERGICSYMPTOMS?Pesticides may be encountered as residues in food, airand water. People may also be exposed to pesticides usedin agriculture, applications for pest control at home or atwork, applications to roadside right-of-ways to controlweeds and applications of pesticides for public healthvector control programs. A specific pesticide exposurewhich might cause an allergic reaction in a susceptibleindividual can be 1,000 times less than an exposurewhich would cause a toxic reaction. For example,exposure to pyrethrum can trigger an asthma attack at atrivial dose of exposure.29-- Traditional African Clinic July 2013WHY DO SOME PEOPLE COUGH, WHEEZE ORSNEEZE WHEN THEY ARE AROUNDPESTICIDE SPRAYS?The answer is not simple. Pesticide products consist oftwo components: the active ingredients whose percentageis very small and the inert ingredients which account forthe bulk of most products. The active ingredient is usually a single, highly purified component although it may bea combination of two or more pesticides. Usually, theinert ingredients consist of carriers such as petroleumdistillates, but may contain other chemicals such asemulsifiers, conditioning agents or wetting agents. Theirability to irritate or sensitize is poorly understood. Somepeople react to the strong odor and irritating effect ofpetroleum distillates. The eyes, the mucous membranesof the nose and even the sensitive linings of the mouthand the back of the throat may feel scratchy. This isusually an annoying symptom which subsides within afew minutes after being removed from exposure to theirritant. Irritation occurs not only with manmade volatilesubstances, but also with naturally occurring substancessuch as perfumes, flowers, or onions. A pesticide productwhich causes someone to develop severe, acuterespiratory symptoms would be a true hypersensitivity toone of the active ingredients. This can occur with alimited number of specific pesticides, all requiringclinical confirmation.Allergic symptoms tend to last for hours or days; irritantsymptoms clear up quickly when the person moves awayfrom the source of exposure. There is no specificdesensitization for pesticide allergy.HOW COMMON IS ALLERGY TO PESTICIDES?Fortunately, few of the thousands of pesticides usedtoday cause true allergic symptoms. Like cosmetics,pesticides are tested for their allergenic potential prior tomarketing. Which pesticide is responsible for the asthmaattack or the rash requires detective work by the patientand the doctor.WHICH PESTICIDES CAUSE ALLERGY?The following list of common names of pesticides hasbeen reported by scientists to be sensitizers in certainsusceptible individuals: allidochlor, anilazine, antu,barban, benomyl, captafol, captan, dazomet,dichloropropane, dichloropropene, lindane, maneb,nitrofen, propachlor, pyrethrum/pyrethroids, rotenone,thiram, zineb.DO PESTICIDE LABELS CARRY ALLERGYWARNINGS?Pesticide labels carry warnings about known healtheffects. Most of these deal with toxicity. Some indicateproblems that have been reported with either irritation toContinued on page 30