Female perineum is very prone to infection because of close proximity of urinary, vaginal and anal orifice.
Next Steps
Start oral as well as topical(cream and soap) antifungal therapy.
also take anti work therapy to clear any worm infestation from your bowels. it is one of the reason of perianal itch.
Health Tips
Avoid tight fitting clothes to avoid spread of infection from one area to other.