Unilateral redness, irritation and itchiness down there. Not yeast. No bumps or anything just red and a bit red and swollen from itchiness.
Still yeast? Several common conditions could do this. Even though you say not yeast, that still may be possible, the most common cause of such symptoms. It can be difficult to identify yeast to confirm the diagnosis, and some yeast infections are caused by Candida glabrata, often resistant to the usual treatments. If your primary care doc or gyn can't figure it out, consider seeing a dermatologist.