Preliminary results of clinical studies using a combination of the heterotricyclic dyes (neutral red and proflavine) and light in the treatment of recurrent cutaneous and mucosal herpes simplex infections have indicated that it is an effective method of therapy. By utilizing the fluorescent properties of proflavine and the fluorescent microscope, we were able to demonstrate that proflavine is readily absorbed percutaneously and is located within the cell nucleus which is the primary site of herpes simplex virus replication.
Bean SF, Felber TD, Knox JM. Proflavine Staining of the Skin Demonstrated by Fluorescent Microscopy. Arch Dermatol. 1973;107(2):204-205. doi:10.1001/archderm.1973.01620170016004