You have not mentioned if you are a man or a woman, and your age. How long has this been happening to you? Itching is a symptom and not a disease. It could happen because of various reasons. If you are sexually active it could be an STD so you need to see a doctor immediately. You'll know the exact reason after examination and medical tests.
If you have shaved or waxed your genital area, it could be the cause of the skin irritation. A change in detergent or if the clothes are not rinsed thoroughly may also cause itching because of the skin reacting to the harsh chemicals.
Change your underwear at least twice in a day and make sure it is clean and washed well. Give a final rinse in an antiseptic solution if you like. Unclean sweaty underwear causes bacterial infection and could also cause itching. Do not use rayon or nylon underwear in hot tropical climate as it blocks the airflow to your skin. The sweat then causes itching. Use natural fabrics like cotton undergarments that allow your skin to breathe. Do not share your personal things like towels, or razors as it increases the chances of infection.
If you have thick growth of pubic hair then Crabs or pubic lice infestation could be the cause. They are tiny six legged creatures. They also thrive in the armpit hair, beard and eyebrows but generally prefer the pubic area. To survive needs human blood, which it draws from the pubic hair follicle. It is their excreta that causes sever itching. Use a magnifying glass in good light and examine at the base of pubic hair. That is where the eggs are laid. Look for adult lice and grayish white small eggs. A contaminated toilet seat, bed sheets, blankets or multiple sexual partners are some of the ways they are transmitted. See your doctor if this is the reason, he will recommend a suitable treatment depending on the severity of the infection. Please avoid trying swimsuits while shopping as these could also cause transmission of crabs if an infected person has worn it before.
Please bathe at least twice a day if you sweat too much or travel and maintain good personal hygiene. Shave or trim your pubic area and keep it clean. Dry skin could also be one of the reasons, so try applying a light fragrance free moisturizer. Do not use soaps with harsh chemicals as these will dry out your skin and cause itching.
answered by G M