Vaginal rash and itching can be caused by many conditions:
One of the commonest causes of itching not associated with discharge in younger age group is contact dermatitis. You should assume this to be the cause first. Treatment is to search for the irritant cause, such as sopa or underwear, etc. You should also take Tab. Alavert10 mg once daily for 10 days.
If you are approaching menopause, or are menopausal, then vaginal thinning associated with menopause is the most likely cause. This can treated fairly simply with estrogen creams, which are available OTC at all pharmacies. Nother common cause is Irritant dermatitis. Treatment is to search for the irritant cause, such as sopa or underwear, etc. You can also take Tab. Alavert10 mg once daily at night .
If this does not help, you should consult your gynaecologist and get checked up. You will also need investigations like a PAP smear. Besides this, you may need to consult a dermatologist if it is not relieved.
You can read up here for some discussion and tips for home treatment. You can also read up here for dermatological causes of vaginal itching.
I hope this answer was helpful. If you need more information, feel free to ask. For accepting this answer, please click on the green 'accept' button below. Feedback/Bonus will be warmly appreciated.