Advancement of interaction organization and continuity in the work of primary and specialized health facilities providing medical care to persons with HIV infection are necessary to improve the quality of care provided to patients with HIV infection. The article describes clinical cases of HIV-associated diseases. It has been shown that despite the alertness to this contingent of patients, it can be difficult to establish a final, including dermatological, diagnosis. An analysis of differential diagnosis and diagnostic search was carried out as an example. Special attention is focused on «high-risk population groups in relation to HIV infection», belonging to which increases the risk of developing not only HIV infection, but also tuberculosis, viral hepatitis, mental disorders and behavioral disorders, sexually transmitted infections. A clinical experience of managing a comorbid patient from the «key population group in relation to HIV infection» is presented. Special attention is paid to the clinical features of chronic dermatosis course in presence of socially significant diseases and communicable diseases, as well as the relationship between lifestyle and adherence to therapy is shown. The presented clinical observations demonstrate that final diagnosis verification remains a difficult task even with high alertness of dermatovenereologists due to variability of clinical picture caused by comorbidity. Increase of the efficacy of interaction between primary care health facilities and specialized centers, optimization of diagnostic and therapeutic algorithms, especially in patients from the «high-risk population groups on socially significant infections», create the conditions for strengthening adherence to treatment, will allow to achieve sustainable clinical outcomes and will improve the quality of life of patients with HIV-associated diseases.