Chemotherapy is often used to treat various types of cancer. These drugs, also called anti-cancer drugs, destroy cancer cells by preventing them from growing and multiplying. However, healthy cells are also harmed during the process, which is responsible for the side effects of treatment. Once chemotherapy is discontinued, healthy cells usually repair themselves and side effects gradually subside.
Common side effects include nausea, vomiting, fatigue, hair loss, anemia, confusion, depression, problems with blood clotting, stomatitis (sores in the mouth), mucosititis (sores in the throat), dry mouth, diarrhea, constipation, loss of appetite, peripheral neuropathy (burning, weakness, tingling or numbness in the hands and/or feet), acne, dry skin, rash, yellow and brittle nails, flu-like symptoms, fluid retention, decreased sperm motility and reduced sexual hormone production in women. Some chemotherapy drugs may also damage the kidneys and/or bladder. Chemotherapy also destroys healthy immune cells. Therefore, patients undergoing chemotherapy are immunocompromised and susceptible to infections.
Sometimes chemotherapy is the only treatment that a patient receives. However, chemotherapy is usually used in addition to other treatments, such as surgery or radiation therapy (treatment that uses high-energy rays to destroy cancer cells).
Chemotherapy is usually administered to help shrink a tumor before surgery or radiation therapy (neo-adjuvant therapy), to help destroy cancer cells that remain after surgery or radiation therapy (adjuvant chemotherapy) or to help destroy cancer if it recurs or has spread to other parts of the body.
Some chemotherapy drugs are used for many different types of cancer, while others are specialized to treat one or two types of cancer. A qualified healthcare provider will recommend a treatment plan based on the type of cancer, where the cancer is located, the effect of cancer on the patient's normal body functions and the patient's overall health.
Chemotherapy is usually administered intravenously (IV). During the procedure, a thin needle is inserted into a vein on the lower arm in order to administer the drug. The needle is removed at the end of the treatment session. Chemotherapy can also be delivered intravenously through catheters, ports or pumps. It can also be taken orally in a capsule or liquid form.
Some patients may experience allergic reactions to chemotherapy. Drug allergies are characterized by a hypersensitive reaction of the immune system to certain medications. Hypersensitivity reactions to chemotherapy, although rare, have been reported with most chemotherapy drugs. The reactions occur most frequently with L-asparaginase, paclitaxel, docetaxel, teniposide, procarbazine and cytarbine. There is a higher risk of allergic reaction if the drug is administered in large doses or if it is administered intravenously.
In some cases, the allergic reaction can be potentially life threatening. The most severe type of allergic reaction, known as anaphylaxis, may occur immediately after taking a drug. Symptoms of anaphylaxis can vary from mild to severe The most dangerous symptoms are low blood pressure, difficulty breathing, shock and loss of consciousness, all of which can be fatal. Anaphylaxis is an emergency condition that requires immediate medical attention. Epinephrine is a medication used to treat severe allergic reactions such as anaphylaxis. Administering the epinephrine as soon as possible improves the patient's chance of survival and a quick recovery.
TYPES OF ALLERGIC REACTIONS
Allergic reactions can be classified into four immunopathologic categories using various classification systems. The Gell and Coombs allergic classification system is based on the immune system's response to the allergen, not on the severity of the reaction. Allergic reactions to drugs, including chemotherapy, is classified as a Type I allergic reaction.
Type I: Type I allergic reactions involve immunoglobulin E (IgE), which is specific for a particular drug, antigen or other allergen that triggers the allergic reaction. The allergen binds to the immunoglobulin on specific immune cells called basophils and mast cells. This binding results in the release of chemicals that cause inflammation in the body (like histamine, serotonin, proteases, bradykinin generating factor, chemotactic factors from immune cells, leukotrienes, prostaglandins and thromboxanes) within 30 minutes of exposure. These chemical mediators cause allergy symptoms, such as urticaria (hives), runny nose, watery eyes, sneezing, wheezing and itching. This type of allergic reaction is often seen with penicillin, latex, blood products and vaccines, among other allergens.
Type II: This classification is called a cytotoxic reaction because it involves the destruction of the host cells. An antigen associated with a specific cell initiates cytolysis of the cell by an antigen-specific antibody, such as immunoglobulin G (IgG) or immunoglobulin M (IgM). This reaction often involves blood elements, such as red blood cells, white blood cells or platelets. It often occurs within five to twelve hours of exposure to the allergen, which may include penicillin, quinidine, phenylbutazone, thiouracils, sulfonamides or methyldopa.
Type III: This category involves the formation of an antigen-antibody immune complex, which deposits on blood vessel walls and activates cell components called complements. This causes a serum sickness-like syndrome, involving fever, swelling, skin rash and enlarged lymph nodes, in about three to eight hours. It may be caused by a variety of allergens, including penicillins, sulfonamides, intravenous (IV) contrast media and hydantoins.
Type IV: This classification involves delayed cell-mediated reactions. Antigens on the allergen release inflammatory mediators within 24 to 48 hours of exposure. This type of reaction is seen with graft rejection, latex contact dermatitis and tuberculin reaction.
SYMPTOMS OF ALLERGIC REACTION
Urticaria (hives): Urticaria (hives) are raised, itchy, red patches of skin. This is a common reaction to chemotherapy drugs, usually occurring 36 hours after drug exposure. In most cases, the lesions clear up within 24 hours. However the next time the drug is administered, urticaria may develop within minutes.
Flushing: Flushing is
a temporary reddening of the face and neck, which is caused by dilation of the blood capillaries.
Angioedema refers to the swelling that occurs in the tissue just below the skin. Angioedema is similar to hives, except it occurs deeper in the skin. The areas of swelling, known as welts, usually appear around the eyes and mouth. Angioedema may also cause the airways to swell, resulting in difficulty breathing. Patients who experience difficulty breathing should seek medical attention immediately.
rash is a common symptom of a drug-induced, allergic skin reaction. The rash consists of red macular (small, distinct, flat areas) and papular (small raised patches of skin) lesions. The rash first appears on the trunk of the body and then spreads to the extremities. It is usually bright red in color, and the skin may feel hot or itchy. This rash can occur with almost any drug and may develop up to two to three weeks after the drug has been administered. However, it usually develops within 10 days of the initial treatment.
This skin reaction may be severe, appearing all over the body (red rash blends together). A severe rash may cause the skin to peel or produce desquamation (areas of wet or dry open sores). Other symptoms of a severe macularpapular rash may include fever, enlarged lymph nodes and loss of appetite.
Anaphylaxis: Anaphylaxis is a rapid, immune-mediated (allergic), systemic reaction to allergens (like chemotherapy) that the individual has previously been exposed to. Anaphylaxis is a medical emergency that requires immediate medical treatment, including epinephrine, as well as follow-up care with an allergist or immunologist. Symptoms of anaphylaxis can vary from mild to severe and may be life threatening. The most dangerous symptoms are low blood pressure, breathing difficulties, shock and loss of consciousness, all of which can be fatal. The most severe type of anaphylaxis, known as anaphylactic shock, will usually result in death within minutes, if untreated. Anaphylactic shock is characterized by inflammation of the throat and a sudden drop in blood pressure. Even trace amounts of the allergen can result in a life-threatening anaphylactic reaction. Anaphylaxis may occur after inhalation, ingestion, skin contact or injection of an allergen.
General: If an allergic reaction to chemotherapy is suspected, it is usually necessary to stop treatment with the offending medication. If the reaction is mild, the chemotherapy agent may be reintroduced and administered with medications that relieve symptoms. However, if a severe reaction like anaphylaxis occurs, the drug might be discontinued permanently.
Mild allergy (localized hives and itching): Treatment focuses on alleviating the symptoms and stopping the allergic reaction. Prescribed medications may include antihistamines, like diphenhydramine (Benadryl©), hydroxyzine (Anx©, Atarax©, Atarax© Syrup or Vistaril©) or cyproheptadine (Periactin©). The individual may be advised to stop taking the allergy-causing medication.
Moderately severe allergy (hives all over the body and itching): Treatment focuses on alleviating the symptoms and stopping the allergic reaction. Prescribed medications may include antihistamines like diphenhydramine (Benadryl©), oral steroids like prednisone or histamine blockers like cimetidine (Tagamet©), famotidine (Pepcid©) or ranitidine (Zantac©). It is usually recommended that the individual stop taking the allergy-causing medication.
Severe allergy (shortness of breath, throat tightness, faintness, severe hives): The allergy-causing medication is stopped immediately. Medications prescribed may include antihistamines like diphenhydramine (Benadryl©), oral or intravenous steroids (like prednisone or methylprednisolone) or histamine blockers like cimetidine (Tagamet©), famotidine (Pepcid©) or ranitidine (Zantac©).
Anaphylaxis: Anaphylaxis is an emergency condition that requires immediate medical attention. CPR should be initiated if the individual is not breathing. Epinephrine is a medication used to treat anaphylaxis. Administering the epinephrine as soon as possible improves the chances of survival and a quick recovery. Epinephrine opens the airways and raises the blood pressure by constricting blood vessels. Patients may also be admitted to the hospital to have their blood pressure monitored and possibly to receive breathing support. Other emergency interventions may also include endotracheal intubation (placing a tube through the nose or mouth into the airway) or emergency surgery to place a tube directly into the trachea (tracheostomy or cricothyrotomy). Low blood pressure is usually treated with intravenous fluids and sometimes with vasoconstrictive medications, also called "pressors." Bronchodilator drugs like Albuterol© are used to treat bronchospasm. After epinephrine or other lifesaving measures are taken, antihistamines (like diphenhydramine) and corticosteroids (like prednisone) may be given to further reduce symptoms.
Individuals with a history of anaphylaxis should carry an autoinjectable epinephrine device (EpiPen©) with them at all times. If symptoms of anaphylaxis appear after exposure to an allergen or medication, the patient uses the device to inject the epinephrine into his/her thigh. A trained family member or friend may help the patient administer the epinephrine, if necessary.
General: Anaphylaxis is considered a medical emergency that requires immediate medical care. Therefore, integrative therapies should not be used in place of conventional medicine when an individual has an anaphylactic reaction.
Acupuncture: Acupuncture plus point-injection has been found beneficial for obstinate urticaria (hives). However, more research is needed to confirm these findings.
There is no known way to prevent an allergic reaction to chemotherapy. However, the less exposure the body has to medications, the less chance the patient will experience an allergic reaction to medication.
Do not take a medication that has caused an allergic reaction in the past. Once an individual has had a reaction to a drug, the risk of having a more severe reaction in the future increases dramatically.
Individuals should inform their healthcare providers, including their dentists, about their allergies and the types of reactions they have had. Patient should tell their healthcare providers if they are taking any drugs (prescription or over-the-counter), herbs or supplements.
Consider wearing a medical alert ID bracelet or necklace, which alerts medical personnel and others about the risk for an allergic reaction.
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
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