HIV infection can be manifested with different skin symptoms, which are sometimes considered infection markers. Erythrodermic psoriasis is a possible manifestation, which is a widespread form of psoriasis. We report a clinical case of a young man suspected of HIV infection due to a psoriatic erythroderma confirmed by biopsies, associated with Kaposi sarcoma. Afterwards, HIV infection was confirmed by serological tests. Antiretroviral therapy was started, with positive response at one month of treatment. Erythrodermic psoriasis can be considered a skin marker of HIV infection when occurs in previously healthy patients or in recalcitrant psoriasis.