Hello Thank you for trusting HCM For pin worm infection your doctor may be advised anti-helmenthic for that you developed allergic reactions. So he advised steroid. Anal itching occurs more often in men, and, most of the time, no cause can be identified. Many causes for anal itching : When a cause can be found, the itching is usually due to irritation of the skin around the anus. Some of the most common irritants include the following: Perfumes, chemicals, or dye on toilet paper can cause an allergic reaction. Moisture from sweat or diarrhea may cause itching. If the anal skin stays wet, the skin begins to break down. Some foods irritate the anus when they are expelled during a bowel movement. Please avoid caffeine,chocolate,beer,nuts, dairy products, and, spicy food. Infections such as pinworms, yeast, and genital warts can cause itching. Hemorrhoids, which cause painful swelling of blood vessels in the anal area, can cause itching. Cancer, in rare instances, may be a cause of anal itching. Tab. Levocegrizine twice a day you can use. Please consult your doctor he will advice correct to you.