Hello, and thanks for your medical question on E Health Forum.
Most cases of anal itching are caused by a harmless problem. Occasionally, however, anal itching can be a sign of more serious medical issues. Possible causes of anal itching include:
1. Dry skin in and around your anus can cause persistent, intense anal itching.
2. Too much moisture around your anus from excessive sweating or from moist, sticky stools can be irritating.
3. Fecal incontinence - Anal itching can also be caused by frequent diarrhea or the escape of small amounts of stool (fecal incontinence).
4. Overuse of laxatives - Excessive or improper use of laxatives can lead to chronic diarrhea and the risk of anal irritation and itching.
5. Chemical irritants. Certain laundry soaps, colognes, douches and birth control products contain chemicals that can irritate skin in and around your anus. Scented or colored toilet paper can be irritating to people with sensitive skin.
6. Skin disorders - Common skin problems â such as psoriasis, seborrhea and eczema â can involve and irritate the area in and around your anus.
7. Yeast infections. This common infection, which usually affects women, can irritate your genital and anal areas.
8. Hemorrhoids. Hemorrhoids are engorged veins located just under the membrane that lines the lowest part of your rectum and anus. They often occur as a result of straining during a bowel movement. Anal itching can be a symptom of hemorrhoids.
9. Anal abrasions, fissures and fistulas. An anal abrasion is a small tear in your anus, usually caused by forced bowel movements through a tight anus. An anal fissure is a deeper tear. An anal fistula is a small tunnel that forms under the skin and connects a previously infected anal gland to the skin on the buttocks outside the anus. All three conditions can cause anal itching, as well as painful bowel movements and bleeding.
10. Food irritants. Anal itching may be the result of irritating chemicals in some foods, such as those found in spices and hot sauces. Similarly, some foods may directly or indirectly irritate your anus as they exit your colon. Common culprits include chocolate, alcohol, tomatoes and citrus fruits. Consuming certain beverages, including milk or caffeinated drinks, may cause some people to experience diarrhea followed by anal itching.
11. Rarely, benign or cancerous tumors in or around the anus ; anxiety or stress.
In addition, excessive scratching and excessive washing can worsen the problem by removing superficial layers of skin.
In your case, the most probable cause might be pinworms, since you ahve had this issue since childhood.
You might consult a doctor for a stool examination and then prescription for deworming can be provided by your doctor.
I hope this helps.