Since Allegra (fexofenadine) is an oral antihistamine, it is often not enough to soothe localized vulvar irritation. For temporary relief, you can apply a thin layer of mild, over-the-counter hydrocortisone cream (1%) or a plain, preservative-free ointment like white petrolatum to the outer area. Avoid scented products and tight clothing. Because these symptoms can stem from various causes like yeast, bacterial vaginosis, or contact dermatitis, I highly recommend visiting a healthcare provider. They can easily diagnose the exact cause and prescribe the right targeted treatment to help you find lasting relief.