A food allergy occurs when the human immune system reacts abnormally to certain foodstuffs. Food allergy is thought to develop more easily in patients with the atopic syndrome, a very common combination of diseases: allergic rhinitis and conjunctivitis, eczema and asthma the syndrome has a strong inherited component; a family history of allergic diseases can be indicative of the atopic syndrome.

Food allergy symptoms are most common in babies and children, but they can appear at any age. You can even develop an allergy to foods you have eaten for years with no problems.

While any food can cause an adverse reaction, the following eight types of food account for about 90 percent of all allergic reactions in India:

• Eggs
• Milk
• Peanuts
• Tree nuts
• Fish
• Shellfish
• Wheat
• Soy

Certain seeds, including sesame and mustard seeds (the main ingredient in the condiment mustard), also are common food allergy triggers and considered a major allergen in some countries.

Symptoms of an allergic reaction may involve the skin, the gastrointestinal tract, the cardiovascular system and the respiratory tract. They can surface in one or more of the following ways:

• Vomiting and/or stomach cramps
• Hives
• Shortness of breath
• Wheezing
• Repetitive cough
• Shock or circulatory collapse
• Tight, hoarse throat; trouble swallowing
• Swelling of the tongue, affecting the ability to talk or breathe in
• Weak pulse
• Pale or blue coloring of skin
• Dizziness or feeling faint

Food Allergy Test

Testing is the most controversial aspect of food allergy. Just getting a skin test or a blood test isn’t enough. The problem is that tests for food allergy are very sensitive. This means that if you do have a food allergy, the tests are very likely to catch it. But the tests aren’t very specific. This means that the tests often are positive when there’s no food allergy. Many children with food allergies become tolerant to those foods over time. This is most likely to happen with allergies to cow’s milk, hen’s eggs, wheat, and soybeans. However, it is least likely to happen with peanut, tree-nut, and seafood allergies.

When a person becomes less sensitive to a food to which he has been allergic to in the past, doctors call it “tolerance.”

Irritated skin can be caused by a variety of factors. These include immune system disorders, medications and infections. When an allergen is responsible for triggering an immune system response, then it is an allergic skin condition. Itching, redness and swelling are common to most skin allergies. Yet there are some differences that help in the diagnosis of specific conditions.

Symptoms

– Atopic Dermatitis (Eczema)
Itchy, red or dry skin. It may “weep” or leak fluid that crusts over when scratched, which means that it is also infected.

In infants, eczema often appears on the face. Children are prone to have the rash at the bends of the elbow joint, wrists, behind the knees and behind the ears. Adolescents and young adults typically have the rash in the same locations as children, as well as on the hands and feet.

Patients with the faulty filaggrin gene often have hand eczema with excessive little lines on the skin of their palms.

– Urticaria (Hives) and Angioedema

Urticaria is itchy, red and white raised bumps or welts that range in size and can appear anywhere on the body. Angioedema often appears on the face around the eyes, cheeks or lips. This deeper layer of swelling can also occur on hands, feet, genitals, or inside the bowels or throat. In acute urticaria, the welts disappear within minutes to a few weeks. Chronic hives last for months or even years.

Phadia Test

It is a commercially available qualitative serological test employed for screening of allergic sensitization in patients with suspected allergic diseases. Phadiatop is a commercially available variant of serum specific IgE assay test that was introduced for the screening of allergic sensitization in 1987

The test has developed successive variants, but all of them have a common principle of the simultaneous testing for serum specific IgE to a mixture of relevant allergens causing common inhalant allergies, food allergies and drug allergies. The test is qualitative, a positive result being suggestive of allergic sensitization.

Phadiatop seemed to provide a valuable and reproducible method to detect overall sensitization to inhalant allergens in a selected population. ImmunoCAP Phadiatop is a blood test designed to differentiate atopic from non-atopic patients.

It is based on Immunocap technology. It consists of a solid-phase immunoassay for serum specific IgE using a balanced mixture of relevant allergens causing common inhalant allergies coupled to ImmunoCAP

Dust allergies also make it difficult to breathe and may trigger Asthma Symptoms, such as wheezing, coughing, tightness in the chest and shortness of breath. Dust also just makes some people itchy.

People with dust allergies often suffer the most inside their own homes or in other people’s homes. Oddly enough, their symptoms often worsen during or immediately after vacuuming, sweeping and dusting given the process of cleaning can stir up dust particles, making them easier to inhale.

Symptoms

• Sneezing
• Runny or stuffy nose
• Red, itchy or teary eyes
• Wheezing, coughing, tightness in the chest and shortness of breath
• Itching

Dust Allergy Triggers (Inhalant Allergens)

• Dust mites
• Cockroaches
• Mold
• Pollen
• Pet hair, fur or feathers

Eye allergies, called allergic conjunctivitis, are a common condition that occurs when the eyes react to something that irritates them (called an allergen). The eyes produce a substance called histamine to fight off the allergen. As a result, the eyelids and conjunctiva — the thin, filmy membrane that covers the inside of your eyelids and the white part of your eye (sclera) — become red, swollen and itchy, with tearing and burning. Unlike bacterial or viral conjunctivitis, allergic conjunctivitis does not spread from person to person.

The most common eye allergy includes:

• Red swollen or itchy eyes
• Burning or tearing of the eyes
• Sensitivity of light

If accompanied by nasal allergies, an infected person may also experience a stuffy, itchy nose and sneezing, as well as a headache, an itchy or sore throat or coughing.

CAUSES:

Many eye allergies are caused by the body’s response to allergens in the air — both indoors and outdoors — such as dust, pet dander, mold, or smoke. Some of the most common airborne allergens include pollen from grass, trees and ragweed, contributing to seasonal allergies.

Allergic reactions to perfume, cosmetics or drugs can also cause the eyes to have an allergic response. Some people may be allergic to the preservative chemicals in lubricating eyedrops.

Sometimes, the eyes can react to other allergens that don’t necessarily come in direct contact with the eye, such as specific types of food or insect bites or stings.

Some people can inherit eye allergies from their parents. A person is more likely to have eye allergies if both the parents have it than if only one has.

Stings from five insects – honeybees, hornets, wasps, yellow jackets and fire ants – are known to cause allergic reactions to the venom injected into the skin. While most people are not allergic to insect venom, the pain from a sting may cause them to mistake a normal reaction for an allergic one. Knowing the difference between a normal reaction and an allergic reaction might save a person trip to the doctor’s office.

Insect stings typically result in pain, swelling and redness confined to the sting site. More severe reactions include symptoms appearing over a wider area (for example, swelling of your whole arm if you were stung on your wrist) or affecting other parts of the body from where the sting occurred.

Symptoms

The stings of five insects – honeybees, hornets, wasps, yellow jackets and fire ants – are known to cause allergic reactions. The severity of an insect sting reaction varies from person to person and from one sting to the next. You may not experience an allergic reaction until you have been stung several times.

There are three types of reactions that can occur:

A normal local reaction will result in pain, swelling and redness confined to the sting site.

A large local reaction will result in swelling well beyond the sting site. For example, a sting on the forearm could cause the whole arm to swell – a condition that usually peaks two to three days after the sting and can last a week or more.

A systemic allergic reaction is the most serious and requires medical attention. Symptoms of a systemic allergic reaction can range from mild to severe. They may include the following (either alone or in combination):

• Hives
• Itchiness
• Flushing
• Swelling in areas away from the sting
• Dizziness or a sharp drop in blood pressure
• A hoarse voice, swelling of the tongue or difficulty swallowing
• Hives, itching and swelling in areas other than the sting site
• Abdominal cramping, vomiting, intense nausea or diarrhea
• Unconsciousness or cardiac arrest

A drug allergy is an allergy to a drug, most commonly a medication. Medical attention should be sought immediately if an allergic reaction to any drug is suspected.If you develop a rash, hives or experience difficulty in breathing after taking certain medications, you may have a drug allergy. As with other allergic reactions, these symptoms can occur when your body’s immune system becomes sensitized to a substance in the medication, perceives it as a foreign invader and releases chemicals to defend against it.

Symptoms

While you may not experience allergic symptoms the first time you take a drug, your body could be producing antibodies to it. As a result, the next time you take the drug, your immune system may see it as an invader, and you’ll develop symptoms as your body releases chemicals to defend against it.

These symptoms may include:

• Skin rash or hives
• Itching
• Wheezing or other breathing problems
• Swelling
• Vomiting
• Feeling dizzy or light-headed
• Anaphylaxis, a potentially life-threatening reaction that can impair breathing and send the body into shock; reactions may simultaneously affect two or more organ systems (for example, when there is both a rash and difficulty breathing)

Penicillin causes most allergic drug symptoms. Just because you show allergic symptoms after taking penicillin doesn’t mean that you will react to related drugs, such as amoxicillin, but it’s more likely. Also, just because you had a reaction to penicillin (or any other drug) at one time doesn’t mean you will have the same reaction in the future.

It occurs when you come into direct contact with an allergen. This type of allergic reaction is known as delayed allergy because it can take several exposures to the allergen to cause a reaction. Also, the symptoms of allergic eczema may not develop for 24 to 48 hours after you have come in contact with the allergen.

Although allergic eczema can develop because of an immune response to any substance, some common triggers include:

• nickel, which can be found in earrings, jewelry, belt buckles, and metal buttons on jeans
• perfumes found in cosmetics
• certain clothing dyes
• hairdressing chemicals and hair dye
• latex
• adhesives
• antibiotic creams or ointments used on the skin such as neomycin

Allergic eczema may also result when the skin is exposed to chemicals in the presence of sunlight. One example is an allergic reaction that occurs after using sunscreen and spending time in the sun.

The symptoms of allergic eczema will be different for each person. They may also change over time. Symptoms typically develop on the skin where contact with the allergen has occurred. In rare cases, symptoms may spread to other areas of the skin.

Symptoms include:

• itching of the skin
• a burning sensation or pain on the skin
• red bumps on the skin that may ooze (weep), drain, or crust
• warm, tender skin
• skin that becomes scaly, raw, or thickened
• skin that becomes dry, red, or rough
• inflammation of the skin
• cuts (fissures) in the skin
• skin rash