Exogenous allergic alveolitis in children

Exogenous allergic alveolitis (ICD-10 code: J-67) - belongs to a group of interstitial lung diseases of known etiology. Exogenous allergic alveolitis is a hypersensitivity pulmonitis with diffuse damage to the alveoli and interstitium. The incidence in children (usually at school age) is lower than in adults (the incidence of exogenous allergic alveolitis is 0.36 cases per 100,000 children per year).

Causes of exogenous allergic alveolitis

Exogenous allergic alveolitis is caused by inhalation of organic dust containing various antigens, microorganisms (for example, thermophilic actinomycetes from rotted hay, the so-called farmer's lung), aspergilli and penicillium. Animal and fish proteins, insect antigens, aerosols of antibiotics, enzymes and other substances. In children, the most common cause of exogenous allergic alveolitis is contact with bird feathers and droppings (the so-called budgerigar lovers' lung or blue-lovers' lung) and elevator dust. In adults, the spectrum of allergens is much wider. For example, cotton dust (babesiosis) or sugar cane dust (bagassosis), sawdust, fungal spores (mushroom growers' lung), fungal dust during cheese production (cheese makers' lung), inhalation drugs of the posterior pituitary gland in patients with diabetes insipidus, etc.

What causes exogenous allergic alveolitis?

Pathogenesis of exogenous allergic alveolitis. Unlike atopic bronchial asthma, in which allergic inflammation of the bronchial mucosa is a consequence of the IgE-dependent reaction of type I, the development of exogenous allergic alveolitis is formed with the participation of precipitating antibodies related to immunoglobulins of the IgG and IgM classes. These antibodies, reacting with the antigen, form large-molecular immune complexes that are deposited under the endothelium of the alveolar capillaries.

Symptoms of exogenous allergic alveolitis. Acute symptoms occur 4-6 hours after contact with the causative antigen. There is a short-term increase in body temperature to high numbers, chills, weakness, malaise, pain in the limbs. Cough is paroxysmal with difficult to separate sputum, dyspnea of a mixed nature at rest and increases with physical exertion. Remote wheezing, cyanosis of the skin and mucous membranes are noted. Upon examination, attention is drawn to the absence of any signs of an infectious disease (primarily acute respiratory viral infection - the absence of hyperemia of the mucous membranes of the pharynx, tonsils, etc.).

Symptoms of exogenous allergic alveolitis

Diagnosis of exogenous allergic alveolitis

The clinical picture of exogenous allergic alveolitis does not depend on the type of allergen. With an acute onset, symptoms resembling flu (chills, fever, headache, myalgia) appear several hours after massive contact with the allergen. Dry cough, shortness of breath, scattered small and medium-sized moist rales appear; there are no signs of obstruction. The picture of asthma is observed in children with atopy. With elimination of the allergen, the symptoms disappear/subside after several days or weeks.

In the hemogram, eosinophilia is not characteristic of this phase of the disease; sometimes slight leukocytosis with neutrophilia is noted.

On the chest X-ray, changes in the form of small (miliary) focal shadows are noted, located mainly in the area of the middle sections of the lungs. Sometimes a picture of decreased transparency of the lung tissue is described - the "ground glass" symptom. Multiple infiltrative cloud-like or denser shadows may also be noted, characterized by reverse development over weeks and months. In some cases, no pronounced X-ray changes are observed. Exogenous allergic alveolitis is characterized by the disappearance of X-ray changes after cessation of contact with the allergen (especially against the background of glucocorticoid therapy).

Diagnosis of exogenous allergic alveolitis

Treatment of exogenous allergic alveolitis

An elimination regimen (stopping contact with the allergen) is mandatory. In the acute phase, glucocorticoids are prescribed, for example, prednisolone up to 2 mg / kg per day orally. The dose should be reduced gradually from the onset of positive dynamics of the clinical picture (reduction of dyspnea, cough, normalization of FVD indicators). Then a maintenance dose of prednisolone 5 mg per day is prescribed for 2-3 months. Option of choice: pulse therapy with methylprednisolone 10-30 mg / kg (up to 1 g) 1-3 days, 1 time per month for 3-4 months.

Treatment of exogenous allergic alveolitis

Prognosis of exogenous allergic alveolitis

The acute phase of exogenous allergic alveolitis has a favorable prognosis when contact with allergens is stopped and adequate treatment is given in a timely manner. When the disease becomes chronic, the prognosis becomes quite serious. Even after contact with the allergen has stopped, the disease continues to progress and is difficult to treat. The situation worsens with the development of pulmonary heart disease.

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