The article is devoted to the study of the causes of the formation of allergic diseases in patients with HIV infection on the example of a clinical case. Patient C., 35 years old, was under medical supervision at the Victory Clinic from 2013 to 2015 with manifestations of skin allergies. Over the next four years, the patient received therapy for exacerbation of atopic dermatitis, followed a diet with the exception of dairy products and beef. The patient’s condition could be assessed as satisfactory; relapses of atopic dermatitis were noted 2 times after a violation of the diet. In 2017, after an unprotected contact, the patient noticed: weakness, weight loss, dry skin and enlarged peripheral lymph nodes. In June 2017, the patient turned to the district pediatrician, who prescribed a referral for a general blood and urine test, a blood test for AIDS and hepatitis. As a result of the examination, the patient was diagnosed with HIV infection. The patient was examined and treated at the Yakutsk AIDS center. Since August 2017, the patient has been worried about nasal congestion, sneezing, watery eyes, and headaches. In early September 2017, the patient turned to an allergist-immunologist. An examination was conducted: a blood test was taken for allergoscreen panel No. 1 and an immunogram, rhinocytogram. The following results were obtained: according to allergoscreen No. 1, allergy to birch 3.0, milk 3.2, wheat flour 2.8. Rhinocytogram data from 09/28/2017: neutrophils 67 per-field and eosinophils 10 per-field. People infected with the human immunodeficiency virus (HIV) have high levels of allergic conditions, including allergic rhinitis (hay fever), drug allergies and asthma. The HIV virus infects and destroys CD4+T cells, a type of white blood cell. This leads to a change in immune function, which contributes to the development of allergies, infections, cancer and other immune problems. In a patient with HIV infection, after the pathology is detected, the formation and transformation of allergic diseases is observed. The formation of allergopathology in HIV patients is associated with a reduced level of CD4+ cells, which is one of the factors contributing to the development of allergy transformation. The treatment of allergic diseases such as: bronchial asthma, atopic dermatitis, allergic rhinitis and allergic urticaria in patients with HIV is the same as in patients not infected with HIV. Oral administration of glucocorticosteroids should be avoided due to the immunosuppressive effects of this group of drugs.