In clinical allergology therapeutic measures for pseudo-allergies are divided into symptomatic and prophylactic. The main condition for prophylactic treatment is the elimination of salicylic acid compounds in the body. Symptomatic treatment is aimed at reducing the level of histamine in the tissues and its activity, which allows to reduce the manifestations of pathology.
- Special diet. The reduction in the diet of the proportion of products containing salicylates, is the main component of preventive therapy. Salicylic acid and its derivatives are predominantly found in plant foods – fruits, nuts, some vegetables and spices.
- Careful selection of skin preparations. A number of cosmetic and external medicines contain salicylates, including as an auxiliary substance. Therefore, when choosing a cream or ointment, you should carefully read its composition.
- Drug prophylaxis. The only group of drugs used to prevent attacks of pseudo-allergy are mast cell membrane stabilizers. Their use allows you to reduce the number of labrocytes that are activated and release histamine in response to the intake of salicylic acid.
- Antihistamine therapy. It refers to symptomatic treatment and is used in the acute period of pseudo-allergy. It includes antihistamines of various generations and any form of release.
- Organ-specific therapy. In an asthma attack, bronchodilator medications are used (beta-adrenoreceptor agonists, etc.). Symptoms of the pollinous allergy to salicylates are alleviated with vasoconstrictor drops and nasal sprays. With the defeat of the stomach antacids will be effective.
Allergy to salicylates has long been known for the reason that drugs based on them (aspirin, acetylsalicylic acid) have long been used in medicine. The first indications of possible intolerance to these drugs appeared at the beginning of the 20th century. The widespread use of antipyretic drugs based on salicylates, as well as the presence of substances in most foods, leads to their massive intake. Exact incidence statistics are unknown – suggest that the proportion of intolerance is up to 30% of the total number of all drug allergies. Among patients there are faces of all ages, women and men suffer from this type of allergy with the same frequency.
Causes of Salicylate Allergy
The exact cause of intolerance to salicylic acid and its derivatives is unknown, there are a number of assumptions and hypotheses on this subject. The complexity of the issue is caused by the fact that this pathological condition is not an allergy in the classical sense, since there is no component of the abnormal immune response of the body. By type, this is a pseudo-allergic reaction, based on the direct effect of salicylates on target cells.
The main theories attempting to explain the occurrence of a condition are as follows:
- Hereditary predisposition There are descriptions of family cases of pseudo-allergies to salicylates, which confirms the view of the possible influence of genetic factors. In particular, there is a hypothesis about altered mast cell receptor proteins, the presence of which makes it possible to develop such intolerance.
- Combination with other allergies. A confirmed fact is the fact that such compounds can exacerbate the manifestations of an existing true allergy. This is due to the ban on the use of acetylsalicylic acid in the treatment of persons with asthma. The explanation for this is that researchers see in the additional membrane destabilization of already activated mast cells.
- Violation of the dosage of drugs. According to this theory, intolerance is possible to cause in any person by taking higher doses of salicylates. Supporters of the hypothesis argue that most of the episodes of this pseudo-allergy are caused by this mechanism. The hypothesis does not explain the cases of development of the pathological state when using optimal and minor amounts of salicylates.
Pathogenesis of allergy to salicylates
Unlike the causes, the pathogenesis of allergy to salicylates has been studied in full. Most of these substances are non-selective inhibitors of cyclooxygenase 1 and 2, due to which they have anti-inflammatory and antipyretic effects. Sometimes they can directly affect the membranes of mast cells (tissue mast cells or labrocytes), destabilizing them and stimulating degranulation.
This leads to the release of biologically active substances (histamine, serotonin, and others), as is the case with the first type of allergic reaction. The secretion of immunoglobulin E, usually stimulating mast cells, does not occur, therefore, intolerance to salicylates is a pseudo-allergy.
Histamine and related compounds have the ability to dilate blood vessels, increase the permeability of the cell wall, affect smooth muscle, and stimulate the mucous glands. Depending on the tissues in which predominant degranulation of mast cells occurs, the clinical picture of the pathological condition depends. During the stimulation of bronchial mast cells, there will be observed a brochospasm with the release of an abundant amount of mucus (as in asthma).
In case of their degranulation, urticaria, redness of the skin, and itching develop in the skin. Sometimes there is an activation of tissue basophils in many organs of the body and the release of a huge amount of histamine, which threatens the development of anaphylactic shock.
Classification of allergy to salicylates
Allergy to salicylates occurs in several basic forms, differing mainly by the involvement of a particular organ or system. Separation is not strict – it is possible a combination of several types of intolerance or the transition of one option to another when the condition worsens. Urticaria may be complicated by allergic rhinitis and conjunctivitis with continued contact of a person with salicylates derivatives.
For the pseudo-allergic condition under consideration, the following forms are characteristic:
- Bronchial type. The main target are the bronchi of various sizes. Under the influence of pseudoallergen, the airway narrows and its additional obstruction with viscous and thick mucus occurs. With existing bronchial asthma, this may complicate the course of the underlying disease and stimulate the development of an attack.
- Dermal type Occurs when the acid compounds enter the skin or on the surface of the skin (as part of medicinal and cosmetic preparations). Characterized by the development of redness and itching, the area and location of the lesion is different in different patients. Sometimes urticaria and swelling of the skin may occur.
- Pollinous type. On the foreground is swelling of the mucous membranes – the nasal cavity and conjunctiva of the eyes. Perhaps the addition of headache, shortness of breath. Mostly develops when taking salicylates inside.
- Abdominal type. Characterized by abdominal pain after taking drugs and products with acetylsalicylic acid and its analogues. The pathogenesis is a spastic contraction of the muscles of the gastrointestinal tract, impaired secretion of gastric juice and reduced protection against the walls of the stomach.
- Edematous type. Occurs after oral administration of salicylates or their contact with the skin. It is characterized by swelling of the subcutaneous tissue of the face, neck, hands and feet.
Severe complication of allergy to salicylates – anaphylactic shock – can occur at any time, regardless of the type of pathological condition. The main role in this is played by the amount of consumed substances of the salicylic acid group: at high dosages, the reaction proceeds harder, and the probability of shock is higher.
This is the main difference between this condition and classical allergy, in which serious consequences can arise from negligible amount of the allergen.
Symptoms of allergy to salicylates
The symptomatology of a pathological condition depends on which system of organs has suffered to a greater degree. Statistically, there are more signs of bronchial tree damage – difficulty breathing, dry rales, cough, expiratory dyspnea (difficulty breathing out). Symptoms occur soon after the use of medicines or food with salicylates and persist for 1-3 days, provided that there is no new allergen intake in the body.
Persons with asthma may develop an attack, its severity depends on the dose of salicylic acid.
Manifestations of the skin form of pseudoallergy are reduced to redness, itching, rash, and other manifestations of urticaria. Damage may occur in areas of direct contact with an irritating substance (when applied externally) or other areas of the skin. Symptoms usually last 2-5 hours, then disappear without a trace. The pollinous type is characterized by the appearance of nasal congestion, sneezing, tearing, feeling cramps in the eyes, headache. The duration of the painful condition ranges from 5-10 hours to 2-4 days.
Abdominal forms of pseudo-allergy are manifested by pain in the epigastric region a few hours after ingestion of drugs or food with salicylates. Their intensity is different, the character is mostly aching or burning. Sometimes nausea, vomiting, diarrhea and other dyspeptic disorders are possible. This condition persists for several hours, however, if you join complications (gastritis, ulcers), its duration may increase.
The edematous type is characterized by a marked swelling of the face, neck, eyelids, and distal extremities soon after taking salicylic acid. The disappearance of edema can take several days.
Complications of allergy to salicylates
The earliest and most severe complication of allergy to salicylates is the development of anaphylactic shock, accompanied by a sharp drop in blood pressure, laryngospasm, fainting. The patient requires urgent medical care, otherwise death is possible.
Other consequences of pseudo-allergy can be bronchial asthma, secondary infection of the conjunctiva of the eyes, nasal cavity, scratching on the skin. The abdominal form can provoke the development of gastritis, peptide stomach ulcers and duodenal ulcers, cases of enteritis are described.
However, such complications are quite rare, after restriction of contact with the allergen, all manifestations of the pathological condition disappear without consequences.
Diagnosis of Allergy to Salicylates
Allergy to salicylates is identified by an allergist-immunologist, diagnostics includes taking the patient’s history, examination, a number of laboratory and instrumental studies, depending on the form of the pathological condition.
The task of a specialist is not only the identification of intolerance to substances such as salicylic acid, but also the differential diagnosis of pathology, which is often significantly difficult. The reason for this is the similarity of the state with many other diseases and significant differences in pathogenesis from typical allergies.
Diagnosis consists of a number of stages:
- Allergist consultation. It is important to identify the relationship between allergic manifestations and the ingestion of products or drugs containing salicylates. It turns out what diseases the patient had previously, what drugs were used to treat them, the preferred food in the diet.
- Allergological testing. To diagnose this condition, a skin allergy test and provocative tests (nasal or conjunctival) with salicylic acid compounds are used. The presence of the reaction (redness, edema) confirms the diagnosis.
- Laboratory and instrumental studies. These methods are often used as auxiliary. These include sputum microscopy, x-rays of the lungs, endoscopy. In the sputum, Charcot-Leiden crystals and eosinophils are often detected, on radiographs – an increase in pulmonary pattern. Fibrogastroscopy reveals signs of hyperacid gastritis, often gastric ulcer.
In general, and biochemical analysis of blood, the only manifestation will be a slight increase in the level of eosinophils. The level of immunoglobulins (in particular, IgE) does not increase.
When interviewing the patient, it is important to clarify exactly which anesthetics he took – in addition to directly salicylates, ibuprofen, indomethacin and NSAIDs similar to them can also lead to the development of pseudoallergy.
Forecast and prevention of allergies to salicylates
Allergy to salicylates is characterized by a favorable prognosis; if pathology is detected and salicylic acid is excluded, the symptoms of pseudo-allergy disappear without any consequences.
Failure to follow the diet and the specialist’s instructions may exacerbate the pathological condition, the increased frequency of which may cause deterioration and the emergence of more severe forms of the disease up to anaphylactic shock.
With high sensitivity to salicylates, a course of mast cell membrane stabilizer preparations and periodic administration of antihistamines are recommended.