Antihistamines can alleviate some of the milder symptoms of an allergic reaction, but do not treat all symptoms of anaphylaxis. Antihistamines block the action of histamine, which causes blood vessels to dilate and become leaky to plasma proteins. Histamine also causes itchiness by acting on sensory nerve terminals. The most common antihistamine given for food allergies is diphenhydramine.

Epinephrine is another name for the hormone adrenaline, which is produced naturally in the body. An epinephrine injection is the first-line treatment for severe allergic reactions (anaphylaxis). If administered in a timely manner, epinephrine can reverse its effects.

Epinephrine relieves airway swelling and obstruction, and improves blood circulation; blood vessels are tightened and heart rate is increased, improving circulation to body organs. Epinephrine is available by prescription in an autoinjector.

Treatment for accidental ingestion of milk products by allergic individuals varies depending on the sensitivity of the person. An antihistamine such as diphenhydramine (Benadryl) may be prescribed. Sometimes prednisone will be prescribed to prevent a possible late phase Type I hypersensitivity reaction. Severe allergic reactions (anaphalaxis) may require treatment with an epinephrine pen, i.e., an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. A second dose is needed in 16-35% of episodes.

The need for a dairy-free diet should be reevaluated every six months by testing milk-containing products low on the "milk ladder", such as fully cooked, i.e., baked foods containing milk, in which the milk proteins have been denatured, and ending with fresh cheese and milk. Desensitization via oral immunotherapy holds some promise but is still being actively researched (see Research).

Treatment for accidental ingestion of milk products by allergic individuals varies depending on the sensitivity of the person. An antihistamine such as diphenhydramine (Benadryl) may be prescribed. Sometimes prednisone will be prescribed to prevent a possible late phase Type I hypersensitivity reaction. Severe allergic reactions (anaphalaxis) may require treatment with an epinephrine pen, i.e., an injection device designed to be used by a non-healthcare professional when emergency treatment is warranted. A second dose is needed in 16-35% of episodes.

There is active research on trying oral immunotherapy (OIT) to desensitize people to egg allergens. A Cochrane Review concluded that OIT can desensitize people, but it remains unclear whether long-term tolerance develops after treatment ceases, and 69% of the people enrolled in the trials had adverse effects. They concluded there was a need for standardized protocols and guidelines prior to incorporating OIT into clinical practice. A second review noted that allergic reactions, up to anaphylaxis, can occur during OIT, and recommends this treatment not be routine medical practice. A third review limited its scope to trials of baked egg-containing goods such as bread or cake as a means of resolving egg allergy. Again, there were some successes, but also some severe allergic reactions, and the authors came down on the side of not recommending this as treatment.

Most people find it necessary to strictly avoid any item containing dairy ingredients. Milk from other species (goat, sheep...) should not be substituted for cow's milk, as milk proteins from other mammals are often cross-reactive. Beyond the obvious (anything with milk, cheese, cream, butter or yogurt in the name), food ingredient lists need to be examined:

- Ghee

- Some Margarine (!)

- Medical food beverages (Ensure, etc.)

- "Non-dairy" coffee creamer

- Eggnog

- Sherbet

- "Cream of..." soups

- Creamy pasta sauces

- Creamy salad dressings

- Nutella

- Simplesse

- Bread

- Baked goods

- Crackers

- Cereals

- Some Chewing gum (!)

- Some Hot dogs (!)

- Instant mashed potatoes

- Flavored potato chips

- Caramel and nougat candy

- casein (milk protein

- whey (milk protein)

- Lactalbumin (milk protein)

- lactoglobulin (milk protein)

- lactoferrin (milk protein)

Probiotic products have been tested, and some found to contain milk proteins which were not always indicated on the labels.

OAS must be managed in conjunction with the patient's other allergies, primarily the allergy to pollen. The symptom severity may wax and wane with the pollen levels. Published pollen counts and seasonal charts are useful but may be ineffective in cases of high wind or unusual weather, as pollen can travel hundreds of kilometers from other areas.

In addition, patients are advised to avoid the triggering foods, particularly nuts.

Peeling or cooking the foods has been shown to eliminate the effects of some allergens such as "mal d 1" (apple), but not others such as celery or strawberry. In the case of foods such as hazelnut, which have more than one allergen, cooking may eliminate one allergen but not the other.

Antihistamines may also relieve the symptoms of the allergy by blocking the immune pathway. Persons with a history of severe anaphylactic reaction may carry an injectable emergency dose of epinephrine (such as an EpiPen). Oral steroids may also be helpful. Allergy immunotherapy has been reported to improve or cure OAS in some patients. Immunotherapy with extracts containing birch pollen may benefit OAS sufferers of apple or hazelnut related to birch pollen-allergens. Even so, the increase in the amount of apple/hazelnut tolerated was small (from 12.6 to 32.6 g apple), and as a result, a patient's management of OAS would be limited.

Completely eliminating salicylate from one's diet and environment is virtually impossible and is not a recommended course of action by many immunologists. The range of foods that have no salicylate content is very limited, and consequently salicylate-free diets are very restricted.

Desensitization involves daily administration of progressive doses of salicylate. This process is usually performed as an inpatient, with a crash-cart at the bedside over a six-day period, beginning with 25 mg of I.V. lysine-aspirin and progressing to 500 mg if tolerated.

Montelukast is one form of treatment used in aspirin-intolerant asthma.

Antihistamines such as diphenhydramine and chlorpheniramine are commonly used as treatment. People treated with H1 antihistamines exhibit reduced production of histamine and leukotrienes as well as downregulation of adhesion molecule expression on the vasculature which in turn attenuates allergic symptoms by 40–50%.

Dual-action medications are also prescribed frequently. Olopatadine (Patanol) and ketotifen fumarate (Alaway or Zaditor) both provide protection by acting as an antihistamine and a mast cell stabilizer together. Patanol is a prescription medication, whereas ketotifen fumarate is not.

A systematic review of 30 trials, with 17 different treatment comparisons found that all topical antihistamines and mast cell stabilizers included for comparison were effective in reducing symptoms of seasonal allergic conjunctivitis. There was not enough evidence to determine differences in long-term efficacy among the treatments.

Many of the eye drops can cause burning and stinging, and have side-effects. Proper eye hygiene can improve symptoms, especially with contact lenses. Avoiding precipitants, such as pollen or mold can be preventative.

Mast cell stabilizers can help people with allergic conjunctivitis. They tend to have delayed results, but they have fewer side-effects than the other treatments and last much longer than those of antihistamines. Some people are given an antihistamine at the same time so that there is some relief of symptoms before the mast cell stabilizers becomes effective. Doctors commonly prescribe lodoxamide and nedocromil as mast cell stabilizers, which come as eye drops.

A mast cell stabilizer is a class of non-steroid controller medicine that reduces the release of inflammation-causing chemicals from mast cells. They block a calcium channel essential for mast cell degranulation, stabilizing the cell, thus preventing the release of histamine. Decongestants may also be prescribed. Another common mast cell stabilizer that is used for treating allergic conjunctivitis is sodium cromoglicate.

For those allergic to fruits, cooking may help reduce or eliminate the reaction to some fruits.

People with this allergy might not necessarily be allergic to citrus fruits.

Individuals can try minor changes of diet to exclude foods causing obvious reactions, and for many this may be adequate without the need for professional assistance. For reasons mentioned above foods causing problems may not be so obvious since food sensitivities may not be noticed for hours or even days after one has digested food. Persons unable to isolate foods and those more sensitive or with disabling symptoms should seek expert medical and dietitian help. The dietetic department of a teaching hospital is a good start. (see links below)

Guidance can also be given to your general practitioner to assist in diagnosis and management. Food elimination diets have been designed to exclude food compounds likely to cause reactions and foods commonly causing true allergies and those foods where enzyme deficiency cause symptoms. These elimination diets are not everyday diets but intended to isolate problem foods and chemicals. Avoidance of foods with additives is also essential in this process.

Individuals and practitioners need to be aware that during the elimination process patients can display aspects of food addiction, masking, withdrawals, and further sensitization and intolerance. Those foods that an individual considers as 'must have every day' are suspect addictions, this includes tea, coffee, chocolate and health foods and drinks, as they all contain food chemicals. Individuals are also unlikely to associate foods causing problems because of masking or where separation of time between eating and symptoms occur. The elimination process can overcome addiction and unmask problem foods so that the patients can associate cause and effect.

It takes around five days of total abstinence to unmask a food or chemical, during the first week on an elimination diet withdrawal symptoms can occur but it takes at least two weeks to remove residual traces. If symptoms have not subsided after six weeks, food intolerance is unlikely to be involved and a normal diet should be restarted. Withdrawals are often associated with a lowering of the threshold for sensitivity which assists in challenge testing, but in this period individuals can be ultra-sensitive even to food smells so care must be taken to avoid all exposures.

After two or more weeks if the symptoms have reduced considerably or gone for at least five days then challenge testing can begin. This can be carried out with selected foods containing only one food chemical, to isolate it if reactions occur. In Australia, purified food chemicals in capsule form are available to doctors for patient testing. These are often combined with placebo capsules for control purposes. This type of challenge is more definitive. New challenges should only be given after 48 hours if no reactions occur or after five days of no symptoms if reactions occur.

Once all food chemical sensitivities are identified a dietitian can prescribe an appropriate diet for the individual to avoid foods with those chemicals. Lists of suitable foods are available from various hospitals and patient support groups can give local food brand advice. A dietitian will ensure adequate nutrition is achieved with safe foods and supplements if need be.

Over a period of time it is possible for individuals avoiding food chemicals to build up a level of resistance by regular exposure to small amounts in a controlled way, but care must be taken, the aim being to build up a varied diet with adequate composition.

Non-sedating antihistamines that block the histamine H1 receptors are the first line of therapy. First generation antihistamines such as diphenhydramine or hydroxyzine block both central and peripheral H1 receptors and can be sedating. Second generation antihistamines such as loratadine, cetirizine, or desloratadine selectively antagonize the peripheral H1 receptors and are less sedating, less anticholinergic, and generally preferred over the first generation antihistamines.

People who don’t respond to the maximum dose of H1 antihistamines may benefit from increasing the dose, then to switching to another non-sedating antihistamine, then to adding a leukotriene antagonist, then to using an older antihistamine, then to using systemic steroids and finally to using ciclosporin or omalizumab.

Oral glucocorticoids are effective in controlling symptoms of chronic hives however they have an extensive list of adverse effects such as adrenal suppression, weight gain, osteoporosis, hyperglycemia, etc. Therefore, their use should be limited to a couple of weeks. In addition, one study found that systemic glucocorticoids combined with antihistamines did not hasten the time to symptom control compared with antihistamines alone.

There is emerging evidence from studies of cord bloods that both sensitization and the acquisition of tolerance can begin in pregnancy, however the window of main danger for sensitization to foods extends prenatally, remaining most critical during early infancy when the immune system and intestinal tract are still maturing. There is no conclusive evidence to support the restriction of dairy intake in the maternal diet during pregnancy in order to prevent. This is generally not recommended since the drawbacks in terms of loss of nutrition can out-weigh the benefits. However, further randomised, controlled trials are required to examine if dietary exclusion by lactating mothers can truly minimize risk to a significant degree and if any reduction in risk is out-weighed by deleterious impacts on maternal nutrition.

A Cochrane review has concluded feeding with a soy formula cannot be recommended for prevention of allergy or food intolerance in infants. Further research may be warranted to determine the role of soy formulas for prevention of allergy or food intolerance in infants unable to be breast fed with a strong family history of allergy or cow's milk protein intolerance. In the case of allergy and celiac disease others recommend a dietary regimen is effective in the prevention of allergic diseases in high-risk infants, particularly in early infancy regarding food allergy and eczema. The most effective dietary regimen is exclusively breastfeeding for at least 4–6 months or, in absence of breast milk, formulas with documented reduced allergenicity for at least the first 4 months, combined with avoidance of solid food and cow's milk for the first 4 months.

An important salicylate drug is aspirin, which has a long history. Aspirin intolerance was widely known by 1975, when the understanding began to emerge that it is a pharmacological reaction, not an allergy.

There is no treatment that will rid the patient of symptoms of aquagenic urticaria. Most treatments are used to lessen the effects of the disease to promote more comfort when the body must come in contact with water.

- Oral antihistamine: Antihistamines such as hydrochloride, hydroxyzine, terfenadine and cyproheptadine have frequently been used to reverse or minimize the effects of aquagenic urticaria. The therapeutic response to these medications will vary from patient to patient and the benefits of applying a histamine antagonist to the skin has not been found to create a direct link to the minimization of water based urticaria effects.

- Topical corticosteroids: Parenteral corticosteroids have been used to help treat aquagenic uricaria in the past. The actual effect of this medication and its benefits are not clear at this time.

- Epinephrine: Patients with severe bouts of urticarial that appear to be acute will frequently use this medication to help decrease the appearance of cutaneous vasodilation. This can also help inhibit mast cell degranulation which may contribute to the presence of aquagenic urticaria.

- PUVA therapy: In one test a 21-year-old woman was given PUVA therapy four times a week in increased doses to help manage the symptoms of aquagenic urticaria. As the dosage was increased the lesions and itching caused by the disease disappeared.

- Ultraviolet radiation: Radiation is commonly used alongside antihistamines to help rid the patient of lesions and outbreaks caused by aquagenic urticaria. This therapy will cause thickening of the epidermis which can prevent water from penetrating this layer and interacting with the cells underneath. Ultraviolet therapy may also cause mast cells to limit their response to stimuli and immunosuppression which can help prevent these reactions.

- Stanazolol: Treatments for the human immunodeficiency virus or HIV have been found to help with the symptoms of aqugenic urticaria as well.

- Capsaicin: This medication is often used for producing Zostrix, a cream applied to lessen pain caused by aquagenic urticaria.

- Barrier methods: In some circumstances an oil in water solution or emulsion cream can be applied to the skin to protect it from water exposure while washing or performing aquatic activities. There does not appear to be a side effect to this method and the application is easier than many other options. Doctors will also recommend that these patients use physical barriers such as an umbrella or protective clothing to avoid contact with water to protect patients from potential outbreaks. Activities such as swimming or visiting a water park will also need to be avoided to minimize the risk of an outbreak.

The more poignant part of this disorder is the lack of desensitization for water and aqua intile injection as allergen even on repeated exposure. Avoidance of allergen as a general principle in any allergic disorder necessitates the evasion of water exposure. Topical application of antihistamines like 1% diphenhydramine before water exposure is reported to reduce the hives. Oil in water emulsion creams, petrolatum as barrier agents for water can be used prior to shower or bath with good control of symptoms. Therapeutic effectiveness of various classes of drugs differs from case to case.

The management of rhinitis depends on the underlying cause.

For allergic rhinitis, intranasal corticosteroids are recommended. For severe symptoms intranasal antihistamines may be added.

Antihistamine agents are the typically prescribed drug for the treatment of physical urticaria. They block the effect of histamine, a compound produced by the body which forms a part of the local immune response consequently causing inflammation. Some research has suggested that the use antihistamines and antagonist in synergy are better for the treatment of physical urticarias.

The cascade of events that link the autoantibody-antigen reaction with the production and release of histamine is not well characterized. Therefore, the focus of treatment for physical urticaria has been on characterizing the effectiveness of antihistamines rather than analysis of receptor binding or the pathomechanisms.

Treatment usually involves adrenaline (epinephrine), antihistamines, and corticosteroids.

If the entire body is involved, then anaphylaxis can take place, which is an acute, systemic reaction that can prove fatal.

Dermographism can be treated by substances (i.e. an antihistamine) which prevent histamine from causing the reaction. These may need to be given as a combination of H antagonists, or possibly with an H-receptor antagonist such as cimetidine.

OTC Vitamin C, 1000 mg daily, increases histamine degradation and removal.

Not taking hot baths or showers may help if it is generalized (all over) and possibly for localized cases (in a specific area). If taking hot showers helps, it may be a condition called shower eczema. If it affects mainly the head, it may be psoriasis. In rare cases, allergy tests may uncover substances the patient is allergic to.

While cromoglycate, which prevents histamine from being released from mast cells, is used topically in rhinitis and asthma, it is not effective orally for treating chronic urticaria.

Risk factors for drug allergies can be attributed to the drug itself or the characteristics of the patient. Drug-specific risk factors include the dose, route of administration, duration of treatment, repetitive exposure to the drug, and concurrent illnesses. Host risk factors include age, sex, atopy, specific genetic polymorphisms, and inherent predisposition to react to multiple unrelated drugs (multiple drug allergy syndrome).

A drug allergy is more likely to develop with large doses and extended exposure.

Drug allergies are attributed to "drug hypersensitivity," otherwise known as objectively reproducible symptoms or signs initiated by exposure to a drug at a dose normally tolerated by non-hypersensitive persons. Drug hypersensitivity reactions are the mediators of a drug allergy.

There are two mechanisms for a drug allergy to occur: IgE or non-IgE mediated. In IgE-mediated reactions, also known as Immunoglobulin E mediated reactions, drug allergens bind to IgE antibodies, which are attached to mast cells and basophils, resulting in IgE cross-linking, cell activation and release of preformed and newly formed mediators.

Few treatments are fully efficacious once lesions have appeared. The only effective form of treatment is preventitive - i.e. prevent further insect bites - so these techniques will also be discussed here. Treatments generally fall into one of the following categories:

1) Insecticides and Repellents: These may be applied to the horse or its environment. The most commonly used and effective are permethrins. and benzyl benzoate Citronella has been used, with variable effect. Some sources advocate draining of any stagnant water or pools, to reduce the local breeding potential of the insects. Midge numbers are often larger near water sources, for example ponds, bogs, and slow moving water. Moving the horse away from these areas may help to prevent further problems.

2) Barrier Techniques: Rugs etc., that prevent flies and midges settling on the animal's skin to bite. These include "Boett Rugs" and fly masks. In addition, thin screens may be placed over stable doors and windows to exclude biting insects. Stabling the horse at times of day when the midges are most prevalent is also quite effective.

3) Immunotherapy: A wide variety immunotherapy and desensitisation protocols have been trialled in attempts to reduce or modify the immune response, with considerable success rates. So far, there appear to a significant benefit in more than 80% of equine cases. This particular BioEos product is now available through The National Sweet Itch Centre in the UK and ProVet in the EU. The underlying immune modulation is now proven to shift the immune system from a Th2 to a Th1 mode. BioEos is a research and development company with worldwide patents derived from many years of research at University College London and the many applications are being developed for use in both human, agricultural and aquaculture treatments. Current clinical trials for the treatment of pancreatic cancers (Immodulon Therapeutics) and the treatment of other chronic immune deficiency disorders (ActinoPharma) are putting this research into practical effect.

4) Nutritional supplements: Various supplements may be effective in individuals, including fatty acid supplemantation and linseed oil. However, although owners perceived an improvement, this was not bourne out by objective statistical analysis.

5) Symptomatic Control: Control of symptoms to some degree can be achieved with antihistamines (especially hydroxyzine, and with corticosteroids, although the potential side effects (e.g. laminitis, immune suppression) make this a less preferred option. In addition, antibiotics may be required to manage any secondary infection.

6) Alternative Medicines: A wide variety of herbal, homeopathic and other alternative remedies have been suggested. Among the natural remedies suggested are sulfur, wild geranium (as the base for a shampoo), Lavender oil, Aloe vera (to reduce the itching).

Overall, the wide variety of treatments proposed leads to the conclusion that no one method is universally effective.