Pollinous conjunctivitis is an allergic condition, one of the components of pollinosis, manifested by inflammation of the conjunctiva of the eyes due to intolerance to the substances of flower pollen of some plants. Symptoms of pathology are lacrimation, itching, burning, redness of the eyes, swelling of the eyelids, photophobia, in severe cases – ulceration of the cornea. Diagnosis is made based on the results of an eye examination, to determine the allergic nature of the condition, skin allergological tests are performed, a blood test for specific IgE. Treatment includes antihistamine therapy, restriction of the patient’s contact with the allergen, local use of anti-inflammatory and vasoconstrictive drugs.
H10.1 Acute atopic conjunctivitis
Pollinous conjunctivitis is a condition with a characteristic seasonal course – exacerbations mainly in spring and summer, in some cases in autumn. The peak incidence occurs during the flowering period of allergen plants, therefore, by the time of the onset of symptoms, a possible allergen can be indirectly detected. The share of pathology in the overall structure of allergic eye diseases is almost half of the cases (45-48%), which makes it the most common allergosis of this type. Pollinosis (allergy to pollen) in about 15% of cases is manifested only by conjunctivitis, in other cases, inflammation of the conjunctiva is accompanied by rhinitis, laryngitis and other allergic lesions. The condition can occur at any age, women suffer more often than men.
Allergic conjunctival lesion is a manifestation of the hypersensitivity reaction of the first type. Allergens are found in the composition of plant pollen, the particles of which are about 20-30 microns in size and spread through the air over considerable distances. The reasons for the intolerance of certain substances with the development of a violent reaction are reliably unknown, the influence of heredity, the reactivity of the organism is assumed. There are a number of predisposing factors of an external and internal nature that contribute to or facilitate the development of an allergic reaction:
- Individual predisposition. The presence of allergic diseases (bronchial asthma, food allergies) increases the risk of symptoms of pollinous conjunctivitis several times. The influence of a genetic factor has been proven – if parents suffer from allergic diseases, the probability of their development in a child is high.
- Environmental factors. Urban residents predominate among the patients. It is believed that this is due to pollution of the urban environment with various chemicals (exhaust gases, factory emissions), which increases the degree of reactivity of the body.
- Biological environment. Pollinosis is caused by pollen of wind–pollinated plants – trees (birch, alder, maple), cereals (wheat, barley, rye) and some weeds (ragweed, quinoa). The presence of parks, squares, flower beds, fields and wastelands with these plants near the patient’s residence leads to a seasonal exacerbation of the disease.
- Climatic factors. The humidity of the air, the amount and frequency of precipitation, the strength and direction of the wind have a decisive influence on the spread of pollen. The probability of the disease increases with dry weather – then pollen particles remain in the air for a long time, can be transported over long distances.
Pollen particles suspended in the air can settle on the exposed mucous membranes of the body – mainly in the nasal cavity and conjunctiva of the eyes. Usually their number is insignificant, in most people the sedimentation process occurs imperceptibly. When sensitizing the body, the ingestion of these dust particles on the mucous membranes causes an inflammatory reaction with characteristic allergic manifestations.
The development of pollinous conjunctivitis is typical for an allergic reaction of anaphylactic type. At the first contact of the body with an allergen that is part of flower pollen, its immunological recognition and sensitization of the body occurs – the appearance of memory cells that trigger an immune response when irritating substances are subsequently ingested. In case of repeated contacts, these cells stimulate the release of a large number of specific immunoglobulins E (IgE) or reagins. The latter are able to activate tissue basophils (mast cells), causing the release of compounds of their granules – histamine, serotonin and a number of other BAS.
Histamine and other substances of its series dilate blood vessels, cause swelling of tissues and other inflammatory manifestations. In the case of pollinosis, this occurs at the place of direct contact with the allergen – pollen settles on the conjunctiva of the eyes, provoking its inflammation, penetrates into the upper respiratory tract. A rarer pathogenetic mechanism of this condition is the so–called cross-allergy – sensitization occurs under the influence of food or other irritating substances, but intolerance also occurs to pollen components. This process can also have a reverse course – the appearance of allergic conjunctivitis sometimes cross-causes urticaria and other reactions to food or household dust.
The pathology is characterized by a pronounced seasonal course due to the flowering period of the plant, the pollen of which acts as an allergen. About a third of patients suffer from ocular manifestations of pollinosis in the spring (April-May), which coincides with the massive release of pollen by wind-pollinated trees (birch, oak, alder). Another seasonal peak of the disease occurs at the end of summer and the beginning of autumn, the flowering time of weeds (quinoa, ragweed). During the first half of summer, pollen particles of wild and cultivated cereal plants (wheat, barley, wheatgrass) can cause pathology. In cities, the autumn form of conjunctivitis is more common – this is due to the widespread spread of weeds (in flower beds, parks, squares) and facilitated contact with an allergen.
The lesion of the eyes is bilateral, it begins quite acutely, usually in the first hours after a walk in the open air, a trip to the countryside. The first manifestations of pathology are itching of the eyes and lacrimation, the development of photophobia (photophobia) is possible. As the inflammation progresses, there is swelling of the eyelid skin, burning, redness of the sclera. The itching becomes very severe, forcing the patient to rub his eyes, which only increases the severity of other symptoms and increases the risk of secondary infection. Corneal lesions and ulceration in pollinous conjunctivitis are usually not observed, but may be the result of infection or mechanical damage during rubbing.
During the entire period of the disease, abundant mucous or serous discharge from the eyes is recorded, sometimes acquiring a purulent character – this indicates the addition of a bacterial infection. The actual ocular manifestations may be accompanied by other symptoms of pollinosis – allergic rhinitis, nasal congestion, sore throat, cough. Small follicular formations, sharply injected vessels are detected on the mucous membrane of the eyes. The duration of the acute period of the disease ranges from 2-5 days to several weeks. The determining role is played by the duration of contact with the allergen, depending on the duration of the flowering period of the pollen source plant, the patient’s lifestyle, climatic and geographical factors.
The most common complication of pollinous conjunctivitis is bacterial infection and purulent inflammation of various severity – from minor secretions to involvement in the process of the skin of the eyelids, cornea (keratitis) and deep structures of the eye. Systemic allergic reactions (Quincke’s edema, anaphylactic shock) are extremely rare. The course of pathology can be complicated by the so–called “pollen intoxication” – headache, fatigue, decreased appetite, nausea. With improper treatment, the transition of the allergic process into a chronic form, the development of cross-forms of allergies, exacerbation of existing diseases is possible.
Determination of pollinous conjunctivitis is carried out on the basis of anamnesis data, physical examination by an ophthalmologist, skin allergological tests. Particular attention is paid to the time of the appearance of the first symptoms – it can be compared with data on the flowering of certain plants in a particular area and, thereby, significantly narrow the list of possible allergens. Laboratory tests play an auxiliary role in the diagnosis – a general blood test, determination of the level of specific IgE, microscopy of conjunctival scraping. The diagnostic algorithm includes the following steps:
- Anamnesis collection, physical examination. The specialist finds out when the symptoms of pathology first appeared, whether they occurred earlier, whether there are other allergic diseases, whether similar conditions were observed in parents. Examination reveals swelling and hyperemia of the conjunctiva, eyelid skin, abundant mucosal discharge.
- Laboratory tests. UAC at the initial stages is unchanged, after 4-5 days, minor eosinophilia is determined. The level of immunoglobulins E is over 100 IU. Microscopy of conjunctival scraping reveals eosinophils, which indicates the allergic nature of inflammation.
- Allergological tests. By comparing the time of the onset of conjunctivitis and the flowering period of the provoking plants, the range of possible allergens that are administered to the patient during application, scarification and other allergy tests is determined. After the end of the acute period, a conjunctival provocative test can be performed to confirm the allergy diagnosis. The presence of a reaction (redness, itching, swelling) allows you to accurately determine the cause of the pathological condition.
A feature of the pathology is the frequent inability to comply with the main principle of the treatment of allergic diseases – the exclusion of contact with the allergen, since pollen is always present in the air during the flowering period and spreads very far. For the treatment of this allergic condition, a large number of techniques are used, used both in the acute period to relieve symptoms and in remission to prevent exacerbations. The following treatment methods are most common:
- Antihistamine therapy. The appointment of antihistamines of general and local action is the leading method of treatment of an acute form of allergic inflammation of the conjunctiva of the eye. Antihistamines reduce the sensitivity of tissues to the contents of mast cell granules, which is why the manifestations of the disease become less pronounced. With a confirmed diagnosis, preventive administration of these drugs is recommended during the flowering of ragweed, cereals and other plants.
- Anti-inflammatory and vasoconstrictors. In severe pathology, local preparations (eye drops) based on hydrocortisone and epinephrine hydrochloride are used. They effectively reduce the severity of inflammation, facilitating the course of the disease and reducing the risk of complications.
- Stabilizers of mast cell membranes. These medications can be used during an exacerbation (locally) or during remission for the purpose of prevention. Derivatives of cromoglycic acid reduce the activity of tissue basophils and reduce the severity of allergic manifestations.
- Allergen-specific immunotherapy (ASIT). It is practically the only etiotropic method of treating pollinous conjunctivitis, can be performed only after an accurate determination of the allergen. The patient is injected with small amounts of a substance that provokes a reaction to develop immunological tolerance. The duration of therapy can range from 3-5 months to several years.
Despite the inability to completely limit the patient’s contact with plant pollen, there are measures that can significantly reduce the amount of allergen entering the body. During the flowering period of plants that are dangerous in allergic terms, the patient should avoid prolonged exposure to the air – especially in dry windy weather, when pollen particles are able to stay suspended for a long time. It is better to plan walks early in the morning or after a light rain – moisture contributes to the settling of pollen. It is not recommended to open windows at home, it is better to use an air conditioner or special incoming air purifying devices. It is necessary to carry out regular wet cleaning. To prevent cross–allergy, certain foods should be excluded from the diet – you can get advice on this from an allergist.
Prognosis and prevention
The prognosis of pollinous conjunctivitis is most often favorable, with properly prescribed treatment or termination of contact with an allergen substance, manifestations of pathology pass without consequences. If the doctor’s prescriptions are not followed, each seasonal exacerbation may be more severe than the previous one – other manifestations of pollinosis (rhinitis, allergic laryngitis) often join the inflammation of the conjunctiva. This is due to the importance of preventive measures during the period of remission of pathology. Monitoring by an allergist-immunologist is often required, since other allergic diseases may occur against this background – cross-food allergy, bronchial asthma.