The signs and symptoms of allergies in a child are:

- Chronic symptoms resembling the cold that last more than a week or two.

- Cold-like symptoms that appear during the same time each year

- Repeated difficulty breathing, wheezing and breathing

- Cold-like symptoms that happen at night

- Cold-like symptoms that happen during exercise

- Chronic rashes or patches of skin that are dry, itchy, look like scales

- Cold-like symptoms that appear after eating a certain food

- Hives

- Swelling of face, arms or legs

- Gagging, coughing or wheezing, vomiting or significant abdominal pain

- Itching or tingling sensations in the mouth, throat or ears

Allergies in children are those causes, pathophsiology, treatments, management, practices and control of allergies that develop in children. Up to 40 percent of children suffer from allergic rhinitis. And children are more likely to develop allergies if one or both parents have allergies. Allergies differ between adults and children. Part of the reason for this that the respiratory system in children is smaller. The bronchi and bronchioles are narrower so even a slight decrease in diameter of these airways can have serious consequences. In addition, children often 'outgrow' their allergies.

The incidence of childhood allergies has increased in the past 50 years.

OAS sufferers may have any of a number of allergic reactions that usually occur very rapidly, within minutes of eating a trigger food. The most common reaction is an itching or burning sensation in the lips, mouth, ear canal, or pharynx. Sometimes other reactions can be triggered in the eyes, nose, and skin. Swelling of the lips, tongue, and uvula and a sensation of tightness in the throat may be observed. It can seldom result in anaphylaxis. If a sufferer swallows the food, and the allergen is not destroyed by the stomach acids, there is a good chance that there will be a reaction from histamine release later in the gastrointestinal tract. Vomiting, diarrhea, severe indigestion, or cramps may occur. Rarely, OAS may be severe and present as wheezing, vomiting, hives and low blood pressure.

The symptoms may vary depending upon the person, the severity of the allergy, and type of fruit. For example, mango allergy symptoms include hoarseness, dyspnoea and bronchitic rales (asthma) (Sareen and Shah). The duration of the symptoms tested by Saree and Shah were variable and ranged from 4 h [11] to 7 days [12]. The symptoms may appear within a few minutes.

Symptoms of an allergic reaction to animals may include itchy skin, nasal congestion, itchy nose, sneezing, chronic sore throat or itchy throat, swollen, red, itchy, and watery eyes, coughing, asthma, or rash on the face or chest.

Food allergies can have fast onset (from seconds to one hour) or slow onset (from hours to several days) depending on mechanism. Symptoms may include: rash, hives, itching of mouth, lips, tongue, throat, eyes, skin, or other areas, swelling of lips, tongue, eyelids, or the whole face, difficulty swallowing, runny or congested nose, hoarse voice, wheezing, shortness of breath, diarrhea, abdominal pain, lightheadedness, fainting, nausea and vomiting. Symptoms of allergies vary from person to person and may vary from incident to incident. Serious danger regarding allergies can begin when the respiratory tract or blood circulation is affected. The former can be indicated by wheezing, a blocked airway and cyanosis, the latter by weak pulse, pale skin, and fainting. When these symptoms occur the allergic reaction is called anaphylaxis. Anaphylaxis occurs when IgE antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show severe symptoms. Untreated, this can proceed to vasodilation, a low blood pressure situation called anaphylactic shock, and death (very rare).

Allergic reactions to fruit and vegetables are usually mild and often just affect the mouth, causing itching, a rash, or blisters where the food touches the lips and mouth. This is called oral allergy syndrome. A number of people who react in this way to fruit or vegetables will also react to pollen from some trees and weeds. So, for example, people who are allergic to birch pollen are also likely to be allergic to apples.

Another symptom may include slight swelling in the throat, making it feel like it is closing. The ability to breathe is still present though, so it is not fatal.

Oral allergy syndrome (OAS) is an allergic reaction in the mouth following eating food. It is a type of food allergy classified by a cluster of allergic reactions in the mouth in response to eating certain (usually fresh) fruits, nuts, and vegetables that typically develops in adults with hay fever.

OAS is perhaps the most common food-related allergy in adults. OAS is not a separate food allergy, but rather represents cross-reactivity between distant remnants of tree or weed pollen still found in certain fruits and vegetables. Therefore, OAS is only seen in people with seasonal pollen allergies, and mostly people who are allergic to tree pollen. It is usually limited to ingestion of only uncooked fruits or vegetables.

Another term used for this syndrome is pollen-food allergy. In adults up to 60% of all food allergic reactions are due to cross-reactions between foods and inhalative allergens.

OAS is a Type 1 or IgE-mediated immune response, which is sometimes called a "true allergy". The body's immune system produces IgE antibodies against pollen; in OAS, these antibodies also bind to (or cross-react with) other structurally similar proteins found in botanically related plants.

OAS can occur any time of the year but is most prevalent during the pollen season. Individuals with OAS usually develop symptoms within a few minutes after eating the food.

Cat allergy in humans is an allergic reaction to one or more allergens produced by cats. The most common of these allergens are the glycoprotein Fel d 1, secreted by the cat's sebaceous glands and Fel d 4, which is expressed in saliva. An allergic reaction is a histamine reaction that is usually characterized by coughing, wheezing, chest tightening, itching, nasal congestion, rash, watering eyes, sneezing, chapped lips, and similar symptoms. In some severe cases, reactions may progress rapidly to cause the victim's airway to become inflamed and close up, requiring emergency medical attention. Those with severe, life-threatening cat allergies face tremendous challenges due to lack of public awareness about anaphylactic cat allergies, and do not enjoy the same conscientiousness from the public as those with a food allergy might, due to widespread knowledge of allergies to allergens such as nuts or dairy.

Food allergies usually have a fast onset (from seconds to one hour) and may include:

- Rash

- Hives

- Itching of mouth, lips, tongue, throat, eyes, skin, or other areas

- Swelling (angioedema) of lips, tongue, eyelids, or the whole face

- Difficulty swallowing

- Runny or congested nose

- Hoarse voice

- Wheezing and/or shortness of breath

- Diarrhea, abdominal pain, and/or stomach cramps

- Lightheadedness

- Fainting

- Nausea

- Vomiting

In some cases, however, onset of symptoms may be delayed for hours.

Symptoms of allergies vary from person to person. The amount of food needed to trigger a reaction also varies from person to person.

Serious danger regarding allergies can begin when the respiratory tract or blood circulation is affected. The former can be indicated through wheezing and cyanosis. Poor blood circulation leads to a weak pulse, pale skin and fainting.

A severe case of an allergic reaction, caused by symptoms affecting the respiratory tract and blood circulation, is called anaphylaxis. When symptoms are related to a drop in blood pressure, the person is said to be in anaphylactic shock. Anaphylaxis occurs when IgE antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show symptoms. Those with asthma or an allergy to peanuts, tree nuts, or seafood are at greater risk for anaphylaxis.

Food allergies usually have a fast onset (from seconds to one hour). Symptoms may include: rash, hives, itching of mouth, lips, tongue, throat, eyes, skin, or other areas, swelling of lips, tongue, eyelids, or the whole face, difficulty swallowing, runny or congested nose, hoarse voice, wheezing, shortness of breath, diarrhea, abdominal pain, lightheadedness, fainting, nausea, or vomiting. Symptoms of allergies vary from person to person and may vary from incident to incident. Serious danger regarding allergies can begin when the respiratory tract or blood circulation is affected. The former can be indicated by wheezing, a blocked airway and cyanosis, the latter by weak pulse, pale skin, and fainting. When these symptoms occur the allergic reaction is called anaphylaxis. Anaphylaxis occurs when IgE antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show severe symptoms. Untreated, this can proceed to vasodilation, a low blood pressure situation called anaphylactic shock, and death (very rare).

Young children may exhibit dermatitis/eczema on face, scalp and other parts of the body, in older children knees and elbows are more commonly afflicted. Children with dermatitis are at greater than expected risk of also exhibiting asthma and allergic rhinitis.

Symptoms of an allergic reaction to cats range from mild to severe, and include swollen, red, itchy, and watery eyes; nasal congestion, itchy nose, sneezing, chronic sore throat or itchy throat, coughing, wheezing, asthma, hay fever, hives or rash on the face or chest, or itchy skin. If a cat has scratched, licked, or bitten someone who is allergic to cats, redness and sometimes even swelling of the affected area will occur. For those severely allergic, a reaction may resemble that of someone with a severe food allergy, and such reactions require emergency medical care.

A typical allergic reaction to alpha-gal has a delayed onset, occurring 3–8 hours after the consumption of mammalian meat products, instead of the typical rapid onset with most food allergies. After the delayed onset, the allergic response is typical of most food allergies, and especially an IgE mediated allergy, including severe whole-body itching, hives, angioedema, gastrointestinal upset, and possible anaphylaxis. In 70% of cases the reaction is accompanied by respiratory distress and as such is particularly harmful to those with asthma.

Alpha-gal allergies are the first food allergies to come with the possibility of delayed anaphylaxis. It is also the first food-related allergy to be associated with a carbohydrate, rather than a protein.

As a result of a possible immunoglobulin E (IgE) allergy to corn, symptoms can resemble that of any other recognized allergy, including anaphylaxis. Reactions to corn derivatives, such as corn syrup, are also possible.

A tree nut allergy is a hypersensitivity to dietary substances from tree nuts and edible tree seeds causing an overreaction of the immune system which may lead to severe physical symptoms. Tree nuts include, but are not limited to, almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios, pine nuts, shea nuts and walnuts.

Tree nut allergies are distinct from peanut allergy, as peanuts are legumes, whereas a tree nut is a hard-shelled nut.

Allergies are caused by an oversensitive immune system, leading to a misdirected immune response. The immune system normally protects the body against harmful substances such as bacteria and viruses. Allergy occurs when the immune system reacts to substances (allergens) that are generally harmless and in most people do not cause an immune response.

- Animal hair and dander

- cockroach calyx

- dust mite excretion

Corn/Maize allergy is a type of food allergy. It can be a difficult allergy to manage, particularly in the United States, due to the various food products which contain various forms of corn, such as corn starch, modified food starch, vinegar, and vanilla extract, among many others. However, it is an allergy that often goes unrecognized.

Some rice proteins are regarded as the causes of allergy in people. People allergic to rice might have sneezing, runny nose, itching, asthma, stomachache or eczema after they eat rice. Besides eating rice, people with a rice allergy can have reactions breathing rice steam from cooked rice. Allergic people might have skin rashes and swellings. Moreover, they might stop breathing and die due to their stopped heart.

Food allergies can have fast onset (from seconds to one hour) or slow onset (from hours to several days) depending on mechanism. Symptoms may include: rash, hives, itching of mouth, lips, tongue, throat, eyes, skin, or other areas, swelling of lips, tongue, eyelids, or the whole face, difficulty swallowing, runny or congested nose, hoarse voice, wheezing, shortness of breath, diarrhea, abdominal pain, lightheadedness, fainting, nausea and vomiting. Symptoms of allergies vary from person to person and may vary from incident to incident. Serious danger regarding allergies can begin when the respiratory tract or blood circulation is affected. The former can be indicated by wheezing, a blocked airway and cyanosis, the latter by weak pulse, pale skin, and fainting. When these symptoms occur the allergic reaction is called anaphylaxis. Anaphylaxis occurs when IgE antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show severe symptoms. Untreated, this can proceed to vasodilation, a low blood pressure situation called anaphylactic shock, and death (very rare).

For milk allergy, non-IgE-mediated responses are more common than IgE-mediated. Non-IgE mediated reactions can manifest as dermatitis/eczema and gastrointestinal symptoms, especially in infants and young children. Infants exhibit dermatiis on face, scalp and other parts of the body, while in slightly older children knees and elbows are more commonly afflicted. Children with dermatitis are at greater than expected risk of also exhibiting asthma and allergic rhinitis.

Many allergens such as dust or pollen are airborne particles. In these cases, symptoms arise in areas in contact with air, such as eyes, nose, and lungs. For instance, allergic rhinitis, also known as hay fever, causes irritation of the nose, sneezing, itching, and redness of the eyes. Inhaled allergens can also lead to increased production of mucus in the lungs, shortness of breath, coughing, and wheezing.

Aside from these ambient allergens, allergic reactions can result from foods, insect stings, and reactions to medications like aspirin and antibiotics such as penicillin. Symptoms of food allergy include abdominal pain, bloating, vomiting, diarrhea, itchy skin, and swelling of the skin during hives. Food allergies rarely cause respiratory (asthmatic) reactions, or rhinitis. Insect stings, food, antibiotics, and certain medicines may produce a systemic allergic response that is also called anaphylaxis; multiple organ systems can be affected, including the digestive system, the respiratory system, and the circulatory system. Depending on the rate of severity, it can cause a skin reactions, bronchoconstriction, swelling, low blood pressure, coma, and death. This type of reaction can be triggered suddenly, or the onset can be delayed. The nature of anaphylaxis is such that the reaction can seem to be subsiding, but may recur throughout a period of time.

People with tree nut allergy are seldom allergic to just one type of nut, and are therefore usually advised to avoid all tree nuts, even though an individual may not be allergic to the nuts of all species of trees.

Someone allergic to walnuts or pecans may not have an allergy to cashews or pistachios, because the two groups are only distantly related and do not necessarily share related allergenic proteins. The severity of the allergy varies from person to person, and exposure can increase sensitization. For those with a milder form of the allergy, a reaction which makes the throat feel like cotton may occur. Subjects allergic to tree nut can experience asthma, skin rashes, itchy throat, swollen eyes. The most severe reaction can lead to anaphylaxis and sensitive subjects may need to carry with them at all times disposable adrenaline injectors prescribed by their GP. Less severe reaction can be dealt with by assuming antihistamines tablet. The raw nut protein usually causes a more severe reaction than the oil, and extra roasting or processing can reduce the allergic reaction. Those diagnosed with anaphylaxis will have a more immediate mast cell reaction and be required to avoid all exposure to any allergen-containing products or byproducts, regardless of processing, as they are prone to even greater sensitivity. An allergy test or food challenge may be performed at an allergy clinic to determine the exact allergens. New immunotherapy treatments are being developed for tree nut allergy.

This allergy tends to be lifelong; recent studies have shown that only about 9% of children outgrow their tree nut allergy.

Hazelnut has been used as a model tree nut in the study of tree nut allergies.

Egg allergy is an immune hypersensitivity to proteins found in chicken eggs, and possibly goose, duck, or turkey eggs. Symptoms can be either rapid or gradual in onset. The latter can take hours to days to appear. The former may include anaphylaxis, a potentially life-threatening condition which requires treatment with epinephrine. Other presentations may include atopic dermatitis or inflammation of the esophagus.

In the United States, 90% of allergic responses to foods are caused by cow's milk, eggs, wheat, shellfish, peanuts, tree nuts, fish, and soy beans. The Food Allergen Labeling and Consumer Protection Act (FALCPA) of 2004 requires that the label of a food that contains an ingredient that is or contains protein from these eight major food allergens declare the presence of the allergen in the manner described by the law. Eggs are also on the mandatory labeling list in Japan and the European Union.

Prevention is by avoiding eating eggs and foods that may contain eggs, such as cake or cookies. It is unclear if the early introduction of the eggs to the diet of babies aged 4–6 months decreases the risk of egg allergies.

Egg allergy appears mainly in children but can persist into adulthood. In the United States, it is the second most common food allergy in children after cow's milk. Most children outgrow egg allergy by the age of five, but some people remain allergic for a lifetime. In North America and Western Europe egg allergy occurs in 0.5% to 2.5% of children under the age of five years. The majority grow out of it by school age, but for roughly one-third, the allergy persists into adulthood. Strong predictors for adult-persistence are anaphylaxis, high egg-specific serum immunoglobulin E (IgE), robust response to the skin prick test and absence of tolerance to egg-containing baked foods.

Identifying a drug allergy can sometimes be the hardest part. Sometimes drug allergies are confused with nonallergic drug reactions because they both cause somewhat similar reactions. Symptoms of a drug allergy can include, but are not limited to, the following list.

- Hives

- Itching

- Rash

- Fever

- Facial swelling

- Shortness of breath due to the short-term constriction of lung airways or longer-term damage to lung tissue

- Anaphylaxis, a life-threatening drug reaction (produces most of these symptoms as well as low blood pressure)

- Cardiac symptoms such as chest pain, shortness of breath, fatigue, chest palpitations, light headedness, and syncope due to a rare drug-induced reaction, eosinophilic myocarditis

Insect sting allergy is the term commonly given to the allergic response of an animal in response to the bite or sting of an insect. Typically, insects which generate allergic responses are either stinging insects (wasps, bees, hornets and ants) or biting insects (mosquitoes, ticks). Stinging insects inject venom into their victims, whilst biting insects normally introduce anti-coagulants into their victims.

The great majority of insect allergic animals just have a simple allergic response – a reaction local to the sting site which appears as just a swelling arising from the release of histamine and other chemicals from the body tissues near to the sting site. The swelling, if allergic, can be helped by the provision of an anti-histamine ointment as well as an ice pack. This is the typical response for all biting insects and many people have this common reaction.

Mosquito allergy may result in a collection of symptoms called skeeter syndrome that occur after a bite. This syndrome may be mistaken for an infection such as cellulitis.

In anaphylactic patients the response is more aggressive leading to a systemic reaction where the response progresses from the sting site around the whole body. This is potentially something very serious and can lead to anaphylaxis, which is potentially life-threatening.

Soy allergy is a type of food allergy. It is a hypersensitivity to dietary substances from soy causing an overreaction of the immune system which may lead to severe physical symptoms for millions of people. The Asthma and Allergy Foundation of America estimates soy is among the eight most common food allergens for pediatric and adult food allergy patients. It is usually treated with an exclusion diet and vigilant avoidance of foods that may be contaminated with soy ingredients. The most severe food allergy reaction is called anaphylaxis and is a medical emergency requiring immediate attention and treatment with epinephrine.