Hi and welcome to the forum! I am glad that I can help you.
You want to know what could be the cause of the symptoms that you experience.
Itching in the genital area may appear in cases of urinary tract infections or vulvovaginitis (infection of the vagina and vulva). During urinary tract infections additional symptoms may appear such as a frequent need to urinate, discomfort or pain during urination, pain in the lower abdomen, milky urine or pus in the urine. In cases of vulvovaginitis itching and rash may appear in the genital area, combined with vaginal discharge.
Given the data that you described, you may or may not be experiencing one of the medical conditions listed above. You may consider having a bacterial culture with an antibiogram from a urine sample to rule out or confirm urinary tract infection. You may also consider seeing a gynecologist for further diagnosis to rule out possible vulvovaginitis. Avoid scratching the skin to prevent additional inflammation and infection of the skin.
Please keep in mind that I provide medical information only. I am not able to diagnose medical conditions online. Please contact your doctor or other qualified healthcare provider such as a gynecologist for further advice and information about diagnosis and treatment options.