Epinephrine (adrenaline) is the primary treatment for anaphylaxis with no absolute contraindication to its use. It is recommended that an epinephrine solution be given intramuscularly into the mid anterolateral thigh as soon as the diagnosis is suspected. The injection may be repeated every 5 to 15 minutes if there is insufficient response. A second dose is needed in 16-35% of episodes with more than two doses rarely required. The intramuscular route is preferred over subcutaneous administration because the latter may have delayed absorption. Minor adverse effects from epinephrine include tremors, anxiety, headaches, and palpitations.

People on β-blockers may be resistant to the effects of epinephrine. In this situation if epinephrine is not effective intravenous glucagon can be administered which has a mechanism of action independent of β-receptors.

If necessary, it can also be given intravenously using a dilute epinephrine solution. Intravenous epinephrine, however, has been associated both with dysrhythmia and myocardial infarction. Epinephrine autoinjectors used for self-administration typically come in two doses, one for adults or children who weigh more than 25 kg and one for children who weigh 10 to 25 kg.

Antihistamines (both H1 and H2), while commonly used and assumed effective based on theoretical reasoning, are poorly supported by evidence. A 2007 Cochrane review did not find any good-quality studies upon which to base recommendations and they are not believed to have an effect on airway edema or spasm. Corticosteroids are unlikely to make a difference in the current episode of anaphylaxis, but may be used in the hope of decreasing the risk of biphasic anaphylaxis. Their prophylactic effectiveness in these situations is uncertain. Nebulized salbutamol may be effective for bronchospasm that does not resolve with epinephrine. Methylene blue has been used in those not responsive to other measures due to its presumed effect of relaxing smooth muscle.

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.

Allergen immunotherapy is useful for environmental allergies, allergies to insect bites, and asthma. Its benefit for food allergies is unclear and thus not recommended. Immunotherapy involves exposing people to larger and larger amounts of allergen in an effort to change the immune system's response.

Meta-analyses have found that injections of allergens under the skin is effective in the treatment in allergic rhinitis in children and in asthma. The benefits may last for years after treatment is stopped. It is generally safe and effective for allergic rhinitis and conjunctivitis, allergic forms of asthma, and stinging insects.

The evidence also supports the use of sublingual immunotherapy for rhinitis and asthma but it is less strong. For seasonal allergies the benefit is small. In this form the allergen is given under the tongue and people often prefer it to injections. Immunotherapy is not recommended as a stand-alone treatment for asthma.

Several medications may be used to block the action of allergic mediators, or to prevent activation of cells and degranulation processes. These include antihistamines, glucocorticoids, epinephrine (adrenaline), mast cell stabilizers, and antileukotriene agents are common treatments of allergic diseases. Anti-cholinergics, decongestants, and other compounds thought to impair eosinophil chemotaxis, are also commonly used. Though rare, the severity of anaphylaxis often requires epinephrine injection, and where medical care is unavailable, a device known as an epinephrine autoinjector may be used.

Currently there is no cure for allergic reactions to peanuts other than strict avoidance of peanuts and peanut-containing foods. Extra care needed for food consumed at or purchased from restaurants. The principal treatment for anaphylaxis is epinephrine as an injection.

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.

Cat allergies can often be controlled with over the counter or prescription medications. Antihistamines and decongestants may provide allergy relief.

Treatment for accidental ingestion of soy 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.

Some allergy sufferers find relief in allergen immunotherapy, a periodic injection therapy designed to stimulate the body's natural immune responses to the cat allergens.

Peanut allergy may be preventable by feeding babies who are at high risk foods that contain peanuts when they are as young as four to six months of age.

Once a nickel allergy is detected, the best treatment is avoidance of nickel-releasing items. It is important to know the main items that can cause nickel allergy, which may be remembered using the mnemonic "BE NICKEL AWARE". The top 13 categories that contain nickel include beauty accessories, eyeglasses, money, cigarettes, clothes, kitchen and household, electronics and office equipment, metal utensils, aliment, jewelry, batteries, orthodontic and dental appliances, and medical equipment. Other than strict avoidance of items that release free nickel, there are other treatment options for reduction of exposure. The first step is to limit friction between skin and metallic items. Susceptible people may try to limit sweating while wearing nickel items, to reduce nickel release and thus decrease chances for developing sensitization and/or allergy. Another option is to shield electronics, metal devices, and tools with fabric, plastic, or acrylic coverings. Dermatological application tests has shown that barrier creams effectively prevent the symptoms of nickel allergy, such as the Nidiesque™.

There are test kits that can be very helpful to check for nickel release from items prior to purchasing. The ACDS providers can give a guidance list of safe items. In addition to avoidance, healthcare providers may prescribe additional creams or medications to help relieve the skin reaction.

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.

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.

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.

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.

The first-line therapy in ColdU, as recommended by EAACI/GA2 LEN/EDF/WAO guidelines, is symptomatic relief with second-generation H1- antihistamines. if standard doses are ineffective increasing up to 4-fold is recommended to control symptoms.

The second-generation H1-antihistamine, rupatadine, was found to significantly reduce the development of chronic cold urticaria symptom without an increase in adverse effects using 20 and 40 mg.

Allergy medications containing antihistamines such as diphenhydramine (Benadryl), cetirizine (Zyrtec), loratidine (Claritin), cyproheptadine (Periactin), and fexofenadine (Allegra) may be taken orally to prevent and relieve some of the hives (depending on the severity of the allergy). For those who have severe anaphylactic reactions, a prescribed medicine such as doxepin, which is taken daily, should help to prevent and/or lessen the likelihood of a reaction and thus, anaphylaxis. There are also topical antihistamine creams which are used to help relieve hives in other conditions, but there is not any documentation stating it will relieve hives induced by cold temperature.

Cold hives can result in a potentially serious, or even fatal, systemic reaction (anaphylactic shock). People with cold hives may have to carry an injectable form of epinephrine (like Epi-pen or Twinject) for use in the event of a serious reaction.

The best treatment for this allergy is avoiding exposure to cold temperature.

Studies have found that Omalizumab (Xolair) may be an effective and safe treatment to cold urticaria for patient who do not sufficiently respond to standard treatments.

Ebastine has been proposed as an approach to prevent acquired cold urticaria.

Avoidance of antitoxins that may cause serum sickness is the best way to prevent serum sickness. Although, sometimes, the benefits outweigh the risks in the case of a life-threatening bite or sting. Prophylactic antihistamines or corticosteroids may be used concomitant with the antitoxin. Skin testing may be done beforehand in order to identify individuals who may be at risk of a reaction. Physicians should make their patients aware of the drugs or antitoxins to which they are allergic if there is a reaction. The physician will then choose an alternate antitoxin if it's appropriate or continue with prophylactic measures.

With discontinuation of offending agent, symptoms usually disappear within 4–5 days.

Corticosteroids, antihistamines, and analgesics are the main line of treatment. The choice depends on the severity of the reaction.

Use of plasmapheresis has also been described.

Treatment consists of two phases: stopping the urushiol contact that is causing the reaction (this must be done within minutes) and, later, reducing the pain and/or itching.

Primary treatment involves washing exposed skin thoroughly with soap, water, and friction as soon as possible after exposure is discovered. Soap or detergent is necessary because urushiol is an oil; friction, with a washcloth or something similar, is necessary because urushiol adheres strongly to the skin. Commercial removal preparations, which are available in areas where poison ivy grows, usually contain surfactants, such as the nonionic detergent Triton X-100, to solubilize urushiol; some products also contain abrasives.

The U.S. Food and Drug Administration recommends applying a wet compress or soaking the affected area in cool water; topical corticosteroids (available over-the-counter) or oral corticosteroids (available by prescription); and topical skin protectants, such as zinc acetate, zinc carbonate, zinc oxide, and calamine. Baking soda or colloidal oatmeal can relieve minor irritation and itching. Aluminium acetate, sometimes known as Burow's solution, can also ease the rash.

Showers or compresses using hot (but not scalding) water can relieve itching for up to several hours, though this "also taxes the skin's integrity, opening pores and generally making it more vulnerable", and is only useful for secondary treatment (not for cleaning urushiol from the skin, which should be done with cold water). People who have had a prior systemic reaction may be able to prevent subsequent exposure from turning systemic by avoiding heat and excitation of the circulatory system and applying moderate cold to any infected skin with biting pain.

Antihistamine and hydrocortisone creams, or oral antihistamines in severe cases, can alleviate the symptoms of a developed rash. Nonprescription oral diphenhydramine (U.S. trade name Benadryl) is the most commonly suggested antihistamine. Topical formulations containing diphenhydramine are also available but may further irritate the skin.

In cases of extreme symptoms, steroids such as prednisone or triamcinolone are sometimes administered to attenuate the immune response and prevent long-term skin damage, especially if the eyes are involved. Prednisone is the most commonly prescribed systemic treatment but can cause serious adrenal suppression, so it must be taken carefully and tapered off slowly. If bacterial secondary infection of affected areas occurs, antibiotics may also be necessary.

Scrubbing with plain soap and cold water will remove urushiol from skin if it is done within a few minutes of exposure. Many home remedies and commercial products (e.g., Tecnu, Zanfel) also claim to prevent urushiol rashes after exposure. A study that compared Tecnu ($1.25/oz.) with Goop Hand Cleaner or Dial Ultra Dishwashing Soap ($0.07/oz.) found that differences among the three—in the range of 56–70% improvement over no treatment—were nonsignificant ("P" > 0.05), but that improvement over no treatment was significant at the same level of confidence.

Further observations:

- Ordinary laundering with laundry detergent will remove urushiol from most clothing but not from leather or suede.

- The fluid from the resulting blisters does "not" spread urushiol to others.

- Blisters should be left unbroken during healing.

- Poison ivy and poison oak are still harmful when the leaves have fallen off, as the toxic residue is persistent, and exposure to any parts of plants containing urushiol can cause a rash at any time of the year.

- Ice, cold water, cooling lotions, and cold air do "not" help cure poison ivy rashes, but cooling can reduce inflammation and soothe the itch.

- Results for jewelweed as a natural agent for treatment are conflicting. Some studies indicate that it "failed to decrease symptoms of poison ivy dermatitis" [1980] and had "no prophylactic effect" [1997]. The juice of the leaves and stems of Impatiens capensis is a traditional Native American remedy for skin rashes, including poison ivy and such use has been supported by at least one peer-reviewed study, as recently as 2012.

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.

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.

Prophylaxis and treatment with an anti-inflammatory agent may stop progression of the reaction. Oral aspirin or ibuprofen every four hours for a day or 60 mg of prednisone orally or intravenously has been used as an adjunctive treatment . However, steroids are generally of no benefit. Patients must be closely monitored for the potential complications (collapse and shock) and may require IV fluids to maintain adequate blood pressure. If available, meptazinol, an opioid analgesic of the mixed agonist/antagonist type, should be administered to reduce the severity of the reaction. Anti TNF-a may also be effective.