Pruritic and dyskeratotic dermatosis (PDD) is an extremely rarely reported condition observed in immunocompromised individuals that is caused by the reactivation of latent human polyomavirus 6 (HPyV6) and human polyomavirus 7 (HPyV7) in the skin. Since its initial description in 2015, several cases have been presented in the literature.

PDD typically presents as widespread, brown to gray, scaly, velvety, or lichenified papules and plaques. Reported areas of involvement include the neck, back, chest, axillae, buttocks, and/or extremities. PDD notably spares the face. PDD is often severely pruritic, resulting in sleep disruption.

Most patients with clinically confirmed PDD are solid organ transplant recipients on chronic immunosuppression who developed the condition years after successful transplant. Additional cases have been described in patients with HIV infection and one with undiagnosed but suspected underlying immunosuppression. Most patients with PDD present chronically with progressive worsening of rash and pruritus without treatment, although a single case of sustained resolution without treatment has been reported in one patient.

HPyV6 and HPyV7 are believed to be common latent viral infections of the skin in the general healthy population. The pathomechanisms of PDD are currently unknown. However, it is hypothesized to be related to viral upregulation of oncogenes in the setting of immunosuppression that results in disorganized and hyperproliferative growth of keratinocytes. Of note, most of the reported solid organ transplant recipients who developed PDD were receiving rapamycin. The significance of this is currently unknown, and further study is needed to clarify how rapamycin affects replication of HPyV6 and HPyV7.