Salicylates sensitivity is a pathological pseudoallergic condition characterized by intolerance to salicylic acid derivatives, which are part of medicines, cosmetics and food. Symptoms vary depending on the nature of the allergic reaction – skin manifestations (rash, urticaria), swelling of the mucous membranes of the eyes and nose, asthmatic attacks, abdominal pain, swelling of the extremities are possible. Diagnosis is made on the basis of studying the patient’s anamnesis, it is possible to conduct allergological tests. Treatment includes restriction of intake of salicylates (correction of treatment, special diets), antihistamine therapy.
Z88.6 Personal history of allergy to analgesic agent
Salicylates sensitivity has been known for a long time due to the fact 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 XX century. The widespread use of antipyretics based on salicylates, as well as the presence of substances in most foods leads to their massive intake into the body. The exact incidence statistics are unknown – it is assumed that the share of intolerance is up to 30% of the total number of all drug allergies. Among the patients there are people of all ages, women and men suffer from this type of allergy with the same frequency.
The exact cause of intolerance to salicylic acid and its derivatives is unknown, there are a number of assumptions and hypotheses on this score. 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 an abnormal immune response of the body. By its type, it is a pseudoallergic reaction based on the direct effect of salicylates on target cells. The main theories trying to explain the occurrence of the condition are the following:
- Hereditary predisposition. There are descriptions of familial cases of pseudoallergia on salicylates, which confirms the opinion about 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. It is a confirmed fact that such compounds can enhance the manifestations of an already existing true allergy. This is due to the ban on the use of acetylsalicylic acid in the treatment of people with bronchial asthma. The researchers see an explanation for this in the additional destabilization of the membranes of already activated mastocytes.
- Violation of drug dosages. According to this theory, intolerance can be caused in any person by taking elevated doses of salicylates. Proponents of the hypothesis claim that this mechanism is caused by most episodes of this pseudoallergia. The hypothesis does not explain the cases of the development of a pathological condition when using optimal and insignificant amounts of salicylates.
Unlike the causes, the pathogenesis of salicylates sensitivity 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 mastocytes or labrocytes), destabilizing them and stimulating degranulation. This leads to the release of biologically active substances (histamine, serotonin and others), as it happens with the first type of allergic reaction. The release of immunoglobulins E, which usually stimulate mastocytes, does not occur, therefore, intolerance to salicylates is pseudoallergic.
Histamine and related compounds have the ability to dilate blood vessels, increase the permeability of the cell wall, affect smooth muscles and stimulate the mucous glands. Depending on which tissues the predominant degranulation of mast cells occurs, the clinical picture of the pathological condition depends. When stimulating bronchial mastocytes, bronchospasm will be observed with the release of copious amounts of mucus (as in asthma). In the case of their degranulation, urticaria develops in the skin, redness of the skin, itching. Sometimes there is 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.
Salicylates sensitivity occurs in several main forms, differing in the predominant involvement of a particular organ or system. The separation is not strict – a combination of several types of intolerance or the transition of one variant to another with deterioration is possible. Urticaria can be complicated by allergic rhinitis and conjunctivitis with continued human contact with salicylate derivatives. The following forms are characteristic of the pseudoallergic condition under consideration:
- Bronchial type. The main target is the bronchi of various calibers. Under the influence of pseudoallergen, there is a narrowing of the respiratory tract and their additional obstruction by viscous and thick mucus. With existing bronchial asthma, this can complicate the course of the underlying disease and stimulate the development of an attack.
- Skin type. Occurs when acid compounds get inside 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 localization of the lesion differs in different patients. Sometimes urticaria and swelling of the skin may occur.
- Pollinous type. Swelling of the mucous membranes – the nasal cavity and conjunctiva of the eyes – comes to the fore. It is possible to attach a headache, difficulty breathing. It mainly develops when taking salicylates inside.
- Abdominal type. It is characterized by abdominal pain after taking medications and products with acetylsalicylic acid and its analogues. The pathogenesis consists in a spastic contraction of the gastrointestinal musculature, a violation of the secretion of gastric juice and a decrease in the protection of the walls of the stomach from it.
- 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.
A severe complication of salicylates sensitivity – 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 salicylic acid group substances consumed: at high dosages, the reaction is more severe, and the probability of shock is higher. This is the main difference between this condition and classical allergy, in which severe consequences can arise from a negligible amount of allergen.
Symptoms of salicylates sensitivity
The symptomatology of the pathological condition depends on which organ system has suffered more. Statistically, signs of damage to the bronchial tree occur more often – difficulty breathing, dry wheezing, cough, expiratory dyspnea (difficulty exhaling). Symptoms occur shortly after the use of medicines or food with salicylates and persist for 1-3 days, provided there are no new allergen intakes in the body. Asthma sufferers may develop an attack, its severity depends on the dose of salicylic acid taken.
Manifestations of the skin form of pseudoallergia are reduced to redness, itching, rash and other manifestations of urticaria. The lesion may occur in areas of direct contact with the irritant (when applied externally) or other areas of the skin. Usually the symptoms persist for 2-5 hours, then disappear without a trace. The pollinous type is characterized by the appearance of nasal congestion, sneezing, lacrimation, a feeling of pain in the eyes, headache. The duration of the painful condition ranges from 5-10 hours to 2-4 days.
Abdominal forms of pseudoallergia are manifested by pain in the epigastric region a few hours after taking medications or eating 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, but with the addition of complications (gastritis, ulcers), its duration may increase. The edematous type is characterized by noticeable swelling of the face, neck, eyelids and distal extremities shortly after taking salicylic acid. The disappearance of edema may take several days.
The earliest and most severe complication of salicylates sensitivity is the development of anaphylactic shock, accompanied by a sharp drop in blood pressure, laryngospasm, fainting. The patient needs urgent medical care, otherwise a fatal outcome is possible. Other consequences of pseudoallergia may 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, peptidic ulcers of the stomach and duodenum, cases of enteritis have been described. However, such complications are quite rare, after limiting contact with the allergen, all manifestations of the pathological condition disappear without consequences.
The allergist-immunologist is engaged in the identification of salicylates sensitivity, the diagnosis includes the collection of the patient’s anamnesis, examination, a number of laboratory and instrumental studies, depending on the form of the pathological condition. The task of the specialist is not only to identify intolerance to substances such as salicylic acid, but also differential diagnosis of pathology, which is often significantly difficult. The reason for this is the similarity of the condition with many other diseases and significant differences in pathogenesis from a typical allergy. Diagnostics consists of a number of stages:
- Consultation with an allergist. It is important to identify the relationship between allergic manifestations and the intake of products or medicines containing salicylates. It turns out what diseases the patient suffered from earlier, what drugs he used for their treatment, preferred foods in the diet.
- Allergological testing. To diagnose this condition, the method of skin allergy tests and provocative tests (nasal or conjunctival) with salicylic acid compounds are used. The presence of a reaction (redness, swelling) confirms the diagnosis.
- Laboratory and instrumental studies. These methods are often used as auxiliary. These include sputum microscopy, lung X-ray, EDS. In sputum, Charcot-Leyden crystals and eosinophils are often detected, and on radiographs – an increase in the pulmonary pattern. Fibrogastroscopy reveals signs of hyperacid gastritis, often stomach ulcers.
In general and biochemical blood analysis, the only manifestation will be a slight increase in the level of eosinophils. The level of immunoglobulins (in particular, IgE) does not increase. When questioning a patient, it is important to clarify which painkillers he took – in addition to salicylates directly, ibuprofen, indomethacin and NSAIDs similar to them can also lead to the development of pseudoallergia.
Treatment of salicylates sensitivity
In clinical allergology, therapeutic measures for pseudoallergia are divided into symptomatic and preventive. The main condition for preventive treatment is the exclusion of salicylic acid compounds from entering the body. Symptomatic treatment is aimed at reducing the level of histamine in tissues and its activity, which reduces the manifestations of pathology. Treatment includes:
- A special diet. Reducing the proportion of products containing salicylates in the diet is the main component of preventive therapy. Salicylic acid and its derivatives are found mainly in plant products – fruits, nuts, some vegetables and spices.
- Careful selection of skin preparations. A number of cosmetic and external medicines contain salicylates in their composition, including as an auxiliary substance. Therefore, when choosing a particular cream or ointment, you should carefully read its composition.
- Drug prevention. The only group of drugs used to prevent pseudoallergic attacks are mast cell membrane stabilizers. Taking them allows you to reduce the number of labrocytes that are activated and secrete histamine in response to the intake of salicylic acid.
- Antihistamine therapy. It refers to symptomatic treatment and is used in the acute period of pseudoallergia. It includes antihistamines of various generations and any form of release.
- Organ-specific therapy. In case of an asthma attack, bronchodilators (beta-adrenergic receptor agonists and others) are used. Symptoms of the pollinous form of salicylates sensitivity are relieved with vasoconstrictive drops and nasal sprays. If the stomach is affected, antacids will be effective.
Prognosis and prevention
Salicylates sensitivity is characterized by a favorable prognosis, when pathology is detected and the intake of salicylic acid is excluded, the symptoms of pseudoallergia disappear without any consequences. If the diet and the prescriptions of a specialist are not followed, exacerbations of the pathological condition are possible, the increased frequency of which can cause deterioration and the appearance of more severe forms of the disease up to anaphylactic shock. With high sensitivity to salicylates, the course use of preparations-stabilizers of mastocyte membranes and periodic administration of antihistamines is recommended.