Numerous plasmacytoid dendritic cell infiltration in HIV‐associated psoriasis relieved only with antiretroviral therapy

The onset of psoriasis is often seen in HIV infection, called HIV-associated psoriasis. Although HIV-associated psoriasis is usually refractory, there are some cases relieved only by antiretroviral therapy. In those cases, the pathogenesis may be formed differently from psoriasis vulgaris. We present the case of a 42-year-old Japanese man with HIV-associated psoriasis. The patient developed a systemic scaly eruption, especially on the soles. Histopathological examination showed typical psoriatic findings and plasma cell infiltration into the dermis. The eruption dramatically remitted with antiretroviral therapy alone, without systemic treatment for psoriasis. In immunohistological findings, few CD4+ cells were seen in the patient's skin. In addition, immunofluorescent staining revealed more BDCA-2 and CD123 double-positive plasmacytoid dendritic cell infiltration into the dermis than that of psoriasis vulgaris. We suggest that the immune response to HIV including plasmacytoid dendritic cell infiltration may involve in the development and remission of HIV-associated psoriasis.