Peanut Allergy

Peanut allergy is considered a major cause of life-threatening hypersensitivity reactions and it is estimated to affect 4 to 8% of children and 1 to 2% of adults.

Peanut allergy, a type of external hypersensitivity, is an abnormal immune response to peanut. In this type of reaction, the immune system is inappropriately triggered by an allergen, which is a food protein or a non-amino acid portion of a protein, such as carbohydrate.

Allergy to peanut usually is lifelong and the allergic symptoms happen throughout the body, from the minor symptoms such as itching tongue or abdominal pain to major systematic reactions or anaphylaxis.

Peanut allergy is the most common cause of food-induced anaphylaxis, a medical emergency which characterized by life-threatening upper airway obstruction, bronchospasm and/or hypotension.

Anaphylaxis is uncommon but not rare, it signs and symptoms can include:
*Constriction of airways
*Inflammation of the throat that makes it difficult to breathe
*Hypotension or a severe drop in blood pressure
*Rapid pulse
*Dizziness, lightheadedness or loss of consciousness

In peanut-induced anaphylaxis IgE reacts with peanut allergens to release messengers such as histamine.
Peanut Allergy

What are the symptoms of food allergy?

Food allergy is defined as an adverse health effect that is due to a specific immune response and occurs reproducibly upon exposure to a given food.

The sign and symptoms of food allergy are frequently overlooked by both patient and physician.  Such signs and symptoms may have multiple possible causes. The most common food allergy signs and symptoms include:
*Tingling or itching in the mouth
*Hives, itching and flaring of eczema rash
*Swelling of the lips, face, tongue and throat or other parts of the body
*Wheezing, nasal congestion or trouble breathing
*Throat tightness, repetitive coughing
*Abdominal pain, diarrhea, nausea or vomiting
*Dizziness, lightheadedness or fainting

Having sudden allergic symptoms within an hour or two of eating a food should raise suspicious of a food allergy. A food allergy can cause chronic daily symptoms that may be more difficult to connect to particular foods.
What are the symptoms of food allergy?

Food sensitivities: definition and prevalence

It is still unclear why certain individuals develop food sensitivities, but the incidence is rising. It is an adverse reaction to a food which other people can safely eat, and includes food allergies, food intolerance, microbial toxications, and chemical sensitivities. Food sensitivities collectively rank among the most common food-related illnesses, although most of the individual types food sensitivities –such as cow’s milk allergy, peanut allergy. Asthma – are rather rare.

A survey (Sloan and Powers 1986) of women’s opinion found that about 30% of the women polled felt that someone in their family had food sensitivity or food allergy.

Studies by Dr. S. Allan Bock of the National Jewish Medical and Research Center in Denver suggest that about 5 percent of all infants under 6 years of age likely risk known diverse reactions to foods.

But of these the most frequently encountered reaction (rash and/or diarrhea after being fed fruit juices) is likely to be non-allergic.

The prevalence allergy is greatest in the first few years of life and decreases over the first decade. For the total population between 1 and 2% of individuals are estimated to be allergy. Among older age groups, food sensitivities are likely to be considerably lower.
Food sensitivities: definition and prevalence 

Mechanisms of food allergy

Allergy causes a vast range of illness. A food allergy is triggered when natural substance is mistaken for a hostile invader, causing immune systems to mobilize to repel the invader.

Allergic reactions may be IgE or non-IgE mediated or may include both types of mechanisms. Food allergies are mediated by IgE antibodies to protein-a characteristic shared with other allergens such as those present in hay fever (an acute allergic nasal condition) an wasp-sting reactions.

The immediate phase is the activation of mast cells and basophils and the release of mediators such as histamine, proteases, leukotrienes and cytokines. The IgE mediated type I reaction is involved in the pathogenesis of many cases of asthma, rhinitis, urticaria and atopic eczema as well as GI adverse reactions to food.

Non-IgE mediated reactions include contact dermatitis, food-protein-induced enteropathy and celiac disease, whereas examples of mixed type reactions are atopic dermatitis, gastroenteritis and asthma.

Allergy mostly affects the body’s interface with the environment – skin, conjunctivitis, airways and gut – but any organ can be affected when the reaction involves the microvasculature.
Mechanisms of food allergy 

Food allergy

A food allergy is an immune system response that creates antibodies to attack substances in a food that human immune system recognized as ‘foreign’.

In the process, the reaction releases huge stores of chemical substances, including histamines, which cause symptoms ranging from a mild case of hives to a potentially life-threatening system shutdown.

People may feel itchy, break out in hives, or get stomach cramps. Some vomit and have diarrhea.

Food allergies affect different people in different ways. Nevertheless, most people with food allergies lead full and happy lives, they enjoy most foods.

People whose parents or their close relatives have allergic disease have a greater tendency than others to develop an allergy at some time in their lives. The most common allergic diseases are asthma,, eczema and hav fever.

When the term ‘allergy’ was first coined, it meant an adverse reaction to any substance that does not bother most people.

Then, in the 1920’s it was discovered that a type of antibody called ‘Reagin’ or IgE was involved in many allergic reactions especially those to inhabitants. So conventional medicine defined allergy as an IgE mediated response.

The number of people affected by allergy has increase dramatically since the early 970s, particularly in developed countries and it continue to increase.
Food allergy