Iodine allergy

Iodine allergy is a type of drug intolerance and is not a common disease. Toxic effects of iodine are most often associated with an overdose of iodine-containing drugs, with the presence of chronic diseases of internal organs and systems, and less often with individual idiosyncrasy.

Excess iodine is dangerous, 3 grams is enough to provoke cardiac and renal failure, but it is quite difficult to do this for the following reasons:

1. Only pure iodine is dangerous, as it is practically impossible to obtain it outside of laboratory conditions, i.e. in everyday life. A fairly harmless form of iodine, inorganic salts or iodides, enters the human body with food or medications.
2. With a small overdose, within 24 hours the concentration of iodides in the blood returns to normal, since iodine is quickly “absorbed” by the thyroid gland and excreted through the urinary system.
3. In order for a deadly dose of pure iodine (3-5 grams) to enter the body, you need to eat several kilograms of seaweed or, as the proverb goes, a pound of salt, but only iodized, which is hardly possible for a person with normal food preferences.
4. Residents of the land of the rising sun - the Japanese - have been consuming iodized foods for centuries, 10-15 times higher than the recommended norm, but are considered one of the healthiest nations on the planet.

However, it is worth paying attention to the fashionable trend of using iodine-containing drugs, which are hoped to cure almost all diseases. Indeed, iodine deficiency can provoke many dysfunctions, but the general craze for iodides has not reduced the overall number of thyroid diseases, unfortunately, statistics say the opposite. Obviously, iodides, like other microelements, are needed by humanity within reasonable limits, beyond which there is not only an allergy to iodine, but also other ailments.

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Causes of Iodine Allergy

Iodine is a microelement from the halogen family, i.e. low-molecular compounds that are in principle incapable of being true allergens. However, iodine can react with antibodies – tissue proteins, form an antigen complex and cause allergy symptoms. Like other medicinal forms, iodine is a hapten that gains molecular weight due to the union with high-molecular protein compounds found in the blood of the human body. Actually, the causes of iodine allergy are the formation of a conjugated antigen, which provokes sensitization and symptoms of an allergic reaction. Any drug containing iodides can become a hapten, these include the following agents:

Inorganic ionic iodides - Kalii iodidum (potassium iodide) and Natrii iodidum (sodium iodide).

• Solutio lodi spirituosa – alcoholic solution of iodine.
• Solutio Lugoli - a solution of iodine in an aqueous solution of potassium iodide, Lugol's solution.
• Radiocontrast agents (intravascular administration) – lipiodol, urografin, ultravist, biligrafin, hexabrix, iodamid, telebrix and others.
• Medicines for the treatment of thyroid diseases – microiodine, antistrumin, thyreocomb, thyreotom, L-thyroxine and others.

• Antiseptic drugs – iodinol, iodovidone, iodoform.
• Antiarrhythmic drugs - amiodarone, sedacorone, cordarone.
• Other groups of drugs include solutan, quiniophone, dermasolone (in the form of an ointment), alvogil, complan, miodil.

The causes of iodine allergy are cross-drug allergies, which can develop in stages:

1. Transformation of an iodine-containing drug (medicinal product) into a form necessary for synthesis with high-molecular proteins.
2. Formation of a complete allergic antigen.
3. Provocation of an allergic reaction by the immune system.

The immune system perceives the antigen complex as pathogenic and fights it with the help of specific immunoglobulins, releasing more than 20 biologically active substances (BAS). The group of BAS primarily includes histamine, then kinin, heparin, serotonin and other components.

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Symptoms of Iodine Allergy

The most typical manifestations and symptoms of iodine allergy are skin rashes and dermatitis. The reaction is so specific that in clinical practice it is called iododermatitis or iodine allergic rash. In addition, localized skin areas may become red at the site of contact with the iodine-containing substance, and swelling may occur less frequently. If iodides have entered the body, the reaction, just like with external contact, manifests itself on the skin. In such cases, skin manifestations are iodine urticaria. In general, iodine allergy symptoms can be divided into two groups:

1. Dermatological manifestations:

Dilation of blood vessels causes redness of the skin.

• Rash, itching.
• Very rarely, in case of severe overdose – erythema multiforme pathological or Stevens-Johnson syndrome.
• Even less common in practice is Lyell's syndrome - toxic bullous dermatitis caused by an allergy to iodine. Most often, isolated cases are associated with the introduction of a radiocontrast agent.

2. Systemic allergic manifestations:

• Difficulty breathing, shortness of breath.
• Erythema of the facial skin.
• Facial swelling.
• Angioedema.
• Quincke's edema.
• Bronchospasm.
• Extremely rare – anaphylaxis, which is considered a pseudo-allergic complication and is diagnosed as anaphylactoid shock.

Allergy to iodine demonstrates quite typical symptoms, as a rule, they do not threaten the health and life of the patient, especially if the allergic reaction is caused by food products (seaweed, sea fish). Complications are possible only with internal use of medicinal iodine-containing agents, severe clinical manifestations are characteristic only with the introduction of radiocontrast agents.

How does iodine allergy manifest itself?

Most often in clinical allergological practice, the so-called iodism is encountered - side effects of an allergic reaction to iodides. The mucous membranes and skin are the first to react, and more severe symptoms are possible with a strong overdose of iodine-containing drugs.

1. A characteristic metallic taste in the mouth.
2. Pain in the gums and teeth.
3. Burning sensation in the airways and mouth.
4. Increased salivation (hypersalivation).
5. Tearing, swelling of the eyes.
6. Allergic rhinitis.
7. A characteristic rash in the form of iodine acne is a papular, pustular rash on the skin of the face, less often on the body.
8. Iododerma is extremely rare – toxic dermatitis in the form of extensive blisters, erythema, purpura (subcutaneous capillary hemorrhages).

How to test for iodine allergy?

How to check for an allergic reaction to iodine-containing drugs? At home, you can conduct a safe test that shows whether the body needs iodides or an allergic response of the immune system is possible. Iodine (alcohol tincture) is applied with a cotton swab to the forearm or thigh (inner side). It is enough to draw several lines or make a small "mesh" that should disappear within 24 hours or earlier. If iodine is completely absorbed through the skin and does not leave a trace on it, then any iodine-containing drug will be perceived quite normally, without complications in the form of allergic reactions. If the skin begins to redden in the place where the lines were applied, you need to stop any contact with iodine and in the future be sure to warn doctors that an individual intolerance to iodine drugs is possible. Iodine may not be absorbed into the skin, but if there are no rashes on it, it does not itch, does not turn red, then the body simply does not need an additional dose of iodides.

How to check for iodine allergy in a medical facility? Before diagnostic procedures involving the introduction of a radiopaque substance, the doctor will definitely find out the allergic predisposition and the possible risk of developing adverse reactions to the drug. Before the introduction of a radiopaque agent, a test is carried out on it, necessarily in a hospital setting. The drug is administered intravenously in a small dose - no more than 2 milliliters. If an allergy to iodine really manifests itself in the form of severe symptoms, they are quickly stopped, and diagnostics are done using more expensive, but safe contrast agents that do not contain iodides. Also, if the need for a diagnostic measure is vital, antihistamines (less often - glucocorticosteroids) are prescribed before the procedure.

In addition, clinicians know that there are chronic diseases that can become a factor provoking an allergic reaction to iodine-containing drugs. For these ailments, tests and tests are not needed, each doctor is familiar with the list and carefully prescribes iodides to patients with a history of the following diseases or conditions:

• Bronchial asthma.
• Cardiovascular diseases that require the use of beta-blockers (beta-blockers) – hypertension, coronary heart disease, heart failure, angina pectoris and other pathologies.
• Latent hyperthyroidism.
• Patients over 60 years of age with neurological disorders.

Diagnosis of iodine allergy

The symptoms of pseudoallergy are very similar to the manifestations of a true allergic reaction, so the diagnosis of iodine allergy requires differentiation. Evaluation of the clinical picture often does not provide complete and accurate information, it is supplemented by various studies, sample tests.

1. The doctor collects anamnestic information, including allergological information. The patient is required to provide a detailed report on any atypical reactions to medications, which may include iodine-containing products. The list of drugs (medicines) should include literally all the products used - from tablets to eye drops or laxative herbal infusions.
2. The doctor determines the time, the period between the intake of iodides or iodine-containing food and the manifestations of allergy. As a rule, the primary symptoms develop several days after the iodine enters the body. Much less often, the reaction occurs after 30-60 minutes, this is direct evidence of the already occurred sensitization and repeated aggressive reaction of the immune system to a familiar antigen.
3. Diagnosis of iodine allergy includes finding out the causes and route of administration of the iodine-containing substance. This may be an external preparation, a medicine in tablet or injection form, or food products. The route of introduction of iodides into the body and their dose are important parameters for confirming the diagnosis - iodine allergy.
4. The patient is prescribed elimination tests, tests in which all drugs are temporarily cancelled. If the patient complains of an allergy to iodides, they are cancelled first, in addition, an elimination diet is prescribed, excluding any type of seafood. In case of iodine intolerance, after elimination, all unpleasant symptoms subside, which confirms an allergy to iodine-containing substances.
5. If diagnostics is complicated by polysymptomatic symptoms characteristic of cross-allergy, skin tests are prescribed. Iodine tests are the application of grids, lines, applications to the forearm area, less often to the inner thigh. As a rule, allergic manifestations are visible after 4-6 hours, sometimes earlier, reddening of the skin and itching are possible.

Diagnosis of iodine allergy when introducing radiocontrast agents is mandatory even if the patient does not present any allergic complaints. The risk of rapid development of bronchospasm, anaphylaxis during the procedure using a contrast agent is high, a test for iodine tolerance helps to avoid potential complications.

Treatment of iodine allergy

The steps to stop an allergic reaction to iodine components are quite typical and include the following:

1. Treatment of iodine allergy is immediate discontinuation of all iodine-containing drugs. Elimination is the most effective way to quickly reduce and neutralize the manifestations of allergy. If there is a suggestion that the symptoms indicate a cross-drug allergy, the drug that does not play an important role in the overall therapeutic prescription and its discontinuation will not worsen the patient's condition is discontinued. 2.
2. Symptomatic treatment of iodine allergy is the prescription of antihistamines according to the clinical picture. The choice of the drug and its form are directly related to the clinical picture of the allergy. In severe complications, such as bronchospasm, anaphylaxis, which is most often called an anaphylactoid reaction to iodine, the relief of symptoms is carried out according to the standard scheme.

If an allergy to iodine manifests itself as iodism, the following regimen is prescribed:

• Discontinuation of iodine-containing drugs.
• Antihistamines in tablet or injection form, depending on the manifestation of the allergic reaction.
• Intravenous administration of calcium chloride; in case of uncomplicated symptoms, oral administration of CaCl2, one tablespoon 2-3 times a day.
• A gentle fractional diet that excludes seafood and iodized salt.
• Enterosorption with the use of Enterosgel and activated carbon.
• Restoration of the microflora of the digestive tract with the administration of enzymatic preparations and eubiotics (bifiform, lactobacterin).
• External antihistamines, antipruritic drugs in the form of ointments (corticosteroids), lotions, aerosols.

Treatment of iodine allergy is, first of all, the relief of the most uncomfortable symptoms, which include skin reactions. Iodine intolerance in the form of contact dermatitis is much more common than pseudo-allergy to radiopaque agents. In case of skin manifestations of allergy, it is enough to thoroughly wash the skin and take an over-the-counter drug from the antihistamine group. When conducting diagnostics using RCS (radiocontrast agents), relief of symptoms and complications is carried out directly in a medical institution, which is not difficult, since the medical staff is basically ready for such actions. It should also be noted that when conducting choledochogography, urography, angiography, iodine allergy occurs in only 1 case per 10,000 procedures.

Prevention of iodine allergy

Preventive measures for LA (drug allergy), which includes iodine intolerance, are the only reliable way to avoid potential complications. If the patient has a history of allergic predisposition, any competent doctor will take this information into account when prescribing diagnostic procedures and basic therapy.

Prevention of iodine allergy is the following rules:

1. Collection of allergy history, including family and hereditary.
2. Elimination of prescriptions and administration of iodine-containing drugs.
3. Exclusion of the prescription of drugs with similar antigenic and immunogenic properties, taking into account the risk of cross-allergy (the entire halogen group - fluorine, iodine, chlorine, bromine).

Consideration of obvious contraindications to the administration of iodides or diagnostic procedures using contrast agents. If possible, procedures should be replaced, or angiography, urography and other diagnostic procedures with the introduction of radiocontrast agents should be carried out with caution in the following conditions and pathologies:

• Hemorrhagic vasculitis.
• Pregnancy.
• Leukopenia.
• Use with caution in hyperthyroidism and thyrotoxicosis.
• Adiposogenital (pituitary) obesity.
• Severe diabetes mellitus.
• Use with caution in case of bronchial asthma, atopic dermatitis.
• Arrhythmia, heart defect, heart failure, angina pectoris, coronary heart disease (CHD).
• Use with caution in hypertension.
• Pulmonary edema.
• Hypercoagulation, dehydration.
• Severe kidney disease, renal failure.

Prevention of iodine allergy is not difficult; most often, iodide intolerance is neutralized by refusing a few drugs or foods that are not vital.