food allergy: overview
Meenakshi BHARKATIYA *, Kamal Singh Rathore, Ankur Maheshwara, Sunita PANCHAWAT, RKNEMA
BN Girls' College of Pharmacy, Udaipur-Raj. 31 002
INTRODUCTION
food allergy is recognized as a common worldwide problem, and, like other atopic diseases, its prevalence appears to be increasing. In recent years, studies of food protein allergy and related immunological reactions have moved on a molecular level, and new found knowledge might provide a new experimental strategy for the laboratory diagnosis and immuno-modulatory control of food induced allergic reactions (1, 2 ).
about 20% of the population alters their diet for perceived reactions to food, but the application of double-blind placebo-controlled oral food challenge, the "gold standard" for diagnosing food allergies, according to the questionnaire based studies estimate the incidence of allergy hranu.Klinički disorders determined by adverse reactions to food can be classified based on immunological or non immunological mechanisms and the organ system or systems affected (3, 4, 5 ).
true incidence of food allergies is less and seems to range from 1% to 4% of the general population and about 6% of the general population and about 6% of the pediatric population, but occur in as much as 25% of children with eczema6 . Allergic hypersensitivity simply put, is a harmful immune reaction to a protein (or allergen) in our environment, which is normally harmless to non-allergic individuals. This may represent a slight itching of the skin, tissue swelling and wheezing, and even progress in the full-blown anaphylaxis and death. 18 million allergy sufferers living in the UK, where 4% of the population also have food allergies.
allergy develops after repeated exposure to a causative allergen. Sensitization occurs on initial exposure (a process that can take up to six weeks to develop) and no reaction occurs during the initial sensitization (6 ).
(a) The definition of
food allergy is an immune response to protein foods, and is caused by allergens in foods that have some kind of protein in food. These proteins resist the cooking process, the stomach acids and enzymes in the stomach and intestines and enter the bloodstream and cause allergic reactions when they enter the bloodstream.
(B) Signs and symptoms of
Symptoms of food allergies are: -
1 Anaphylaxis : - severe, whole-body allergic reaction that can lead to death. Leads to vasodilation and, if severe, life-threatening symptoms of shock.
2 Angioedema:. - rapid swelling (edema) of the skin, mucosa and submucosal tissues, especially the eyelids, face, lips, tongue, and
3 Eczema is a form of dermatitis, or inflammation of the upper layers of the skin.
(a). Atopic eczema (aka infantile e., e. bending, atopic dermatitis) is believed to have hereditary component and often runs in families whose members also have hay fever and asthma. Itchy rash is particularly noticeable on the face and scalp, neck, inside the elbows, behind knees, and buttocks.
(b). Contact dermatitis is of two types: allergic (resulting from the delayed reaction to some allergen, such as poison ivy or nickel) and irritant (resulting from direct reaction solvent, for example). Some substances act as an allergen and irritant (eg wet cement). Other substances cause a problem after sunlight exposure, which is on phototoxic dermatitis.
(c). Xerotic eczema (aka asteatotic e., e. craquelé or craquelatum, winter itch, itching and evergreen ) is dry skin that becomes so serious it turns into eczema. It worsens in dry winter weather, and limbs and torso are usually pogođeni.Svrbež, the sensitivity of the skin resembles a dry, cracked, river bed. This disorder is very common in the elderly population.
(d). Seborrhoeic dermatitis (aka cradle cap in infants, dandruff) causes dry or greasy scaling of scalp and eyebrows. Scaly pimples and red patches sometimes appear in various adjacent places. In the infant causes a thick, yellow crusty scalp rash called cradle cap which seems related to lack of biotin, and is often curable.
4 Rashes , such as hives (also called urticaria or hives). Some of those enduring a rash called atopic dermatitis.
5 Itchy mouth, throat, eyes, skin or any area of
6 Nausea, vomiting, diarrhea, abdominal cramps, abdominal pain, or
7 Running nose or nasal congestion
8 Wheezing, scratchy throat, difficulty breathing, or difficulty swallowing
9 Mood swings, depression symptoms of immunoglobulin E (IgE) allergic reactions can take place within a few minutes to an sat.Proces eating and digesting food affects the time and place of the reaction. IgG reactions build over a period of several hours to days, and therefore the symptoms can be difficult to notice as an allergy-related (7).
TYPE OF FOOD allergy
There are several food groups that are responsible for causing the majority of food allergy (6). Rice allergy is more common in East Asia, where rice is a large part of the diet. In Central Europe, celery allergy is more zajedničkog.Vrh allergens vary from country to country but milk, eggs, peanuts, tree nuts, fish, shellfish, soy, wheat and sesame tend to be in the top ten in many countries (8) .
the most food allergies are: -
1 Allergy to cow's milk :-
Two of the children under one year of age suffer from allergies to cow's milk, which is usually food allergies in children. In general children lose this sensitivity as they grow up to nine out of ten you lose it at the age of three, it is unusual for adults to suffer from this allergy. Symptoms are frequently vomiting and diarrhea in children, with 30-50% also have a rash on the skin of some vrsta.Mali number of children an anaphylactic reaction to milk, which tends to be lifelong.
major allergens in milk proteins are casein and b-lactoglobulin. People are usually allergic to more than one type of protein mlijeka.Proteini from cow's milk are very similar to those of goats and sheep. Thus, goat or sheep's milk can not be used as a replacement for cow's milk allergic people (8).
Report on the 22-year-old female patient is described who repeatedly hospitalized for severe asthma attacks because of the likely intake of cow's milk or dairy products that contain it. There were no signs of gastrointestinal disorders, but some urticaria and angioedema occurred. Very positive RASTs (Radioallergosorbent test) was recorded in the blood serum against the protein in cow's milk, bovine serum albumen, cod and home prašine.Simptomi have successfully managed to strict dietary measures (8).
2 Eggs :-
allergy to eggs is usually observed in young children than adults, as well as cow's milk allergy, fades with time. Sometimes children suffer from severe allergies that is not outgrown.
The main allergens are the egg white proteins ovomucoid, ovalbumin and ovotransferrin.Jaja other poultry such as ducks, are very similar to those of chickens and can cause reactions in egg allergic individuals (8).
3 Allergies to peanuts :-
Peanut is one of the most commonly allergenic foods and often cause serious reactions, including anaphylaxis. Peanut allergy is established in childhood and usually takes place throughout life. Peanut allergies can be so severe that only very small amounts of peanut can cause a reaction. Thus, traces of nuts found in processed oils, or carryover of materials on utensils for serving food, may be sufficient in some individuals, cause reakciju.Glavni allergens in peanuts and soy proteins are used as a seed food store for it to grow into seedlings. One of the allergen in soy is very similar to the major allergen from dust mites, a common environmental allergen. We're still not sure whether this means that there is a connection between allergies and soy dust allergies.
a large number of children who develop allergies to peanuts have a first reaction the first time were given peanut containing product (usually a peanut butter stain). A large number of children who develop allergies to peanuts have a first reaction the first time are given containing peanut products (usually a peanut butter stain). Peanut proteins can pass into breast milk eight three p.m. breastfeeding women, aged 21-35 years ate 50 grams of dry roasted peanuts (about 60 peanut butter or 1 / 3 cup). Breast milk samples were collected at hourly intervals. Peanut protein is found in breast milk from 11 mothers. In 10 mothers, it is detected within two hours after eating peanuts, one mother was discovered six hours later.
peanut protein in breast milk, so sensitize the child who is at risk for developing allergies. This may explain why up to 85 percent of children had a reaction to peanut allergies for the first time they eat peanut-product that it sadrži.Beba born in a family with allergies.
[Note: - milk, eggs and wheat have previously been shown to pass into the breast mlijeko.Majke family allergic to eliminate peanuts and tree nuts (eg almonds, walnuts, etc.) and take into account the removal of eggs, milk , fish, and perhaps other foods from their diets while nursing. If you decide to do this, be sure to talk with a registered dietitian to make sure that your diet is balanced (8 ).
4 Tree Nut Allergy :-
This group includes true nuts like Brazil nuts, hazelnuts, pecan nuts in. While not as extensively studied as peanuts, indications are that nuts can cause serious symptoms that can sometimes be fatal. Children who become more sensitive to tree nuts tend to remain allergic throughout life. Hazelnut and almond allergies are more like those people to come to fruit, and are linked to pollen allergies. Nut allergens can be destroyed, and resistant, for cooking and frying think we can actually create new alergene.Alergena can be the seed storage proteins or other molecules that are also found in pollen.
5 Fish and shellfish allergies: -
Allergies to shellfish are unusual in children, mostly experienced by adults. Reactions to the fish found in children and odraslih.Incidencija seafood allergy is higher in countries with high consumption of fish and shellfish. Severe reactions are more frequently found with these foods, including anaphylaxis. Cooking does not destroy the allergens in fish and shellfish, and some individuals may be allergic to cooked but not raw, ribe.Glavni allergens in fish flesh proteins called parvalbumins which are very similar in all species of fish. Shellfish allergens are usually found in the body and are part of muscle protein, while in food such as shrimps, allergens are also found in shellfish.
If you are pregnant or trying to be, avoiding seafood and shellfish. Some believe that this may cause your child to develop food allergies.
6 Fruit allergy :-
In general, allergic reactions to fruits and vegetables are mild and are often limited to the mouth, called oral allergy syndrome (OAS). About four out of ten people who have the OAS are also allergic to pollen, weeds and trees. So people who are allergic to birch pollen are much more likely to be allergic to apples. There allergens in fruits and vegetables are not as complicated as other foods. Many of them are as highly allergenic pollen, which is why people with allergies to pollen are also allergic to certain fruits.
Many fruit allergens are destroyed by cooking, and thus cooked fruits are often safe for fruit allergic people to eat. Allergies to latex gloves, especially among health care workers, are increasing. Like many of the latex allergens are like those of some tropical fruits such as bananas, these people can get an allergic reaction to handling or eating these foods (8). Tomato allergy - reported in four cases (two adults with throat constriction, one child with gastro esophageal reflux disease [GERD], a child with atopic dermatitis) with IgE-mediated reactions to tomatoes
.Using extracts prepared from the skin, seeds, and fleshy fruit of the tomato-specific IgE antibodies in the serum of patients was detected by ELISA. After marking extracts for antigen profile and reactivity with IgE, the proteins were separated by SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Of the four patients, one adult showed more IgE against tomato skin extract. Western blot examination of the patient rabble with tomato skin extract also revealed a reaction with a protein band of 42-45kD region. Tomato allergy may manifest as atopic dermatitis, laryngeal angioedema, and even gastroesophageal reflux.
7 Cereal allergy:
suffered children and adults alike, wheat allergy seems to be particularly associated with exercise-induced anafilaksije.Više grains (wheat, rye, barley, oats, corn or rice) we eat are likely to suffer allergies. Thus rice allergy is more common in populations eating ethnic diets. The seed storage proteins (such as wheat gluten) and other proteins present in the grain to protect it from attacks mold and bacteria have been found to be major allergens.
8 Penicillin allergy is a reaction:
is often the event - a rash, itching, hives and fever. Wheezing, angioneuritis, edema, serum sickness and exofolliative dermatitis are rare. Anaphylaxis is rare but can be fatal. Fear of anaphylactic shock several injPnG limited use in general practice. All forms of penicillin (natural or semi-synthetic) can cause an allergy, but it is more commonly seen after parenteral administration.
to produce penicillin hypersensitivity - urticaria, angioedema, bronchiospasm, anaphylaxis or serum sickness. If the previous reaction was just a rash, penicillin can be given cautiously - often no adverse effect is seen. The history of penicillin allergy should be elicited before injection njega.Ispočetka test an intradermal test (s 20-10 in) can be performed in the first place. On the occasion of his has caused fatal anaphylaxis. Testing with benzyl penicilloyl - polylysine safer. However, a negative intradermal test does not rule out delayed hypersensitivity. It should also be released to the presence of antibodies to penicillin allergy does not mean it, because almost everyone who receives penicillin develop antibodies to it.
for the development of antibodies, penicillin, or the product is (mostly penicilloyl half - a major determent) acting as a hapten. Topical use of penicillin is very sensitive (contact dermatitis and other reactions). Therefore, any topical preparations of penicillin (including eye ointment) are prohibited, except for use in the eye as a solution in the case of gonococcal opthalmia (9 ).
Classification of food allergy
1 Immediate reaction of the type (or sensitive skin wheal TIP)
antibodies: Skin sensitizing :-
A. Hereditary : spontaneous, sudden, apparently, often severe symptoms, including all major body systems such as Portal
(a) Alimentary mucosa causes: food ingestion
(b) causes respiratory mucosa: Inhalation of airborne food dust and volatile food odors breathing (rare)
(c) of the skin causes: food percutaneous absorption (rare)
(d) parenteral injections: therapeutic agent-containing foods excitants
B. Nonhereditary induced, anaphylactic, often severe symptoms that include all the major systems of the body
Portal of entry: For parenteral injection causes: sensitizers such as organ extracts, viral vaccines (egg media)
2 Delayed REACTION WHATSOEVER (skin negative or WHEALTYPE)
antibody: unknown :-
A. Hereditary: intentional, just the symptoms include all major systems
body
Portal of entry: Alimentary mucosa causes: food ingestion
B. Nonhereditary - Induced (contact dermatitis), a rare, including skin and respiratory systems
Portal of entry: intact oral, and oral mucosa and skin causes: food, essential oils of foods and spices (10 ).
Pathophysiology
food allergy is an immune response to protein foods food allergies, type 1 hypersensitivity reaction. Type I hypersensitivity is characterized by excessive activation of mast cells and basophils by IgE, resulting in systemic inflammatory response that can lead to symptoms as benign as a runny nose, life-threatening anaphylactic shock and death.
exposure to the allergen-activated B cells to form IgE secreting cells plazmi.Izlučuje IgE molecules bind specific IgE Fc receptors on mast cells. Second exposure to allergens leads to cross linking of IgE bound trigger the release of pharmacologically active mediators vasoactive amines (11 ).
Immunoglobulin E (IgE ):
potent biological activity of IgE allowed to be identified in the serum despite the extremely low average serum concentrations (0.3microgram/ml). IgE antibodies mediate immediate hypersensitivity reactions that are responsible for the symptoms of hay fever, asthma, rashes and anaphylactic shock. Where appropriate antigen injected later in the same place, wheal and flare reaction develops. This reaction, called PK reaction was the basis for the first biological test for IgE activity.
IgE binds to Fc receptors on the membranes of blood basophils and tissue mast cells, cross-linking or receptor bound IgE molecules of antigen (allergen) causes basophils and mast cells in the expulsion of their granules to the plasma membrane and release their contents extracellular environment, a process known as degranulation. As a result, a variety of pharmacologically active mediators are released and rise to allergic manifestations.
Fc receptors
Many cells have membrane glycoproteins called Fc receptors (FCR), which have an affinity for the Fc part of antibody molecules. These receptors are essential for many functions bioligocal antibodies. FCR binds IgE, such as: - cytoplasmic domain FcRI chains are associated with protein tyrosine kinases (PTKs). Crosslinkage of FcRI receptor activates the associated PTKs, resulting in phosphorylation of tyrosines in the ITAMs of the subunits, as well as phosphorylation of residues in the subunits and the phospholipace C. These events phosphyrylation incduce producton number of second messengers that mediate the process of degranulation.
within 15 s after crosslinkage of FcRI, methylation of various membrane phospholipids was observed, which resulted in increased membrane fluidity and the formation of Ca2 + channels. The increase in Ca2 + levels peak within 2 min. of FcRI crosslinkage. This increase is due to the entry of extracellular Ca2 + and Ca2 + release from stores nitracellular in the endoplasmic reticulum. Ca2 + increase at the end leads to the formation of arachidonic acid, which is converted into two classes of potent mediators:. prostaglandins and leukotrienes increase in Ca2 + and promotes microtubule assembly and contraction of microfilaments, both of which are necessary for the movement of granules to the plasma membrane of the importance of Ca2 + increase. in mast cell degranulation noted the use of drugs such as disodium cromoglycate (cromolyn sodium), which block the flow as a treatment for allergies (11 ).
side effect of phospholipid methylation and Ca2 + increase, there was a transient increase in activity of membrane-bound adenylate cyclase, with rapid peak reaction products, cyclic adenosine monophosphate (cAMP), reaching around min. after crosslinkage of FcRI. impact camping is done through the activation of cAMP-dependent protein kinases, which phosphorylate proteins on the granule membrane, which changes the permeability of granules for water and Ca2 +. consequent swelling of the granules facilitates their attachment to the plasma membrane, releasing their contents increased in a transient camp, followed by a decline in the camp at the lower levels of basic This decline in the camp seems to be necessary for degranulation to proceed; .. when cAMP levels are increased by certain drugs, degranulation process is blocked. histamines are the main mediator of food allergies (11 ).
IgE Crosslinkage initiate degranulation
of biochemical events mediate degranulaton mast cells and blood basophils are many common features. For simplicity, this section provides a general overview of the mechanisms of mast cell degranulation without calling attention to the small differences between mast cells and basophils. Although mast cell degranulation mainly runs allergen crosslinkage of bound IgE, a number of other stimuli can also initiate the procedure, including the anaphylatoxins (C3a, C5a and C4A) and various drugs. This section focuses on the biochemical events that follow allergen crosslinkage of IgE bound to follow
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