Peritus ani (PA) is a common localized pruritus. It is sometimes mildly itchy in the anus, but becomes pruritus if the itching is severe and persists over time. It is a common confined neurological dermatosis. It is usually limited to the perianal area, and some may spread to the perineum, vulva or the back of the scrotum. It occurs mostly in the middle and old age of 20 to 40 years old, less frequently in young people under 20 years old, and rarely in children. It is more common in men than in women, and this pruritus occurs more often in people who are used to quiet and infrequent exercise. Secondary pruritus has an obvious causative cause and is easily treated; spontaneous or unexplained PA is not easily cured and also often recurs, accounting for about 50% of all patients.
Anal pruritus is mostly seen in middle-aged people. Partially localized symptoms of generalized pruritus are seen mostly in the elderly. Pruritus confined to the anal area is mostly associated with or secondary to anal and rectal disease. Local inflammation and congestion increase skin circulation and temperature, and the buttocks are not easy to dissipate heat, which leads to increased sweat excretion and moist impregnation, causing discomfort and itching. Patients with the first onset of itching often use hot water to scald the skin or apply drugs containing corticosteroids topically for a longer period of time, which can temporarily relieve itching, but over time can form a vicious cycle of itching – bad stimulation – more itching, making the local symptoms even more dramatic. The itching can also be caused by eating spicy food, poor hygiene habits, not timely cleaning of the anus perineum, scratching and rubbing across the pants, can make the itching intensify. Poor dressing, wearing narrow clothes and pants, or wearing uncomfortable texture of underwear such as some chemical fiber fabrics or thick and rough, so that the buttocks around the sweat is not easily distributed and friction can also trigger anal itching. In children, anal itching is mostly caused by pinworm disease, in which female pinworms worm their way out of the anus to oviposit, creating mechanical stimulation that causes anal itching.
PA can be divided into primary itching and secondary itching according to the cause.
1.Primary pruritus
Primary pruritus is not accompanied by primary skin damage, with pruritus as the main symptom.
2.Secondary pruritus
Secondary pruritus arises from primary diseases and various skin diseases, accompanied by obvious specific skin damage and primary lesions, pruritus is often a symptom of the primary lesion. For example, anal itching caused by anal fistula, anal eczema, warts, neurodermatitis, anorectal tumors, pinworms, etc. all belong to this category.
The initial anal itching is light, with no obvious changes in the anal skin, mostly paroxysmal. In patients with prolonged disease, itching is more intense and lasts longer, especially at night. Excessive scratching or mechanical stimulation makes the perianal skin hypertrophy and roughness, deepens the anal folds, local scratches, blood scabs, ooze, and residual fecal dirt in the folds, and in more severe cases, infection can be combined with pus vesicles or purulent secretions, flushing and swelling. The lesions may extend to the perineum, scrotum, female vulva and even the skin of both buttocks. Clinical examination may reveal internal hemorrhoids, external hemorrhoids, mixed hemorrhoids, anal fistula, or laboratory tests may reveal diabetes mellitus, pinworms, and Candida albicans infection.
Based on the typical history of anal pruritus, combined with clinical symptoms and signs, it is not difficult to diagnose the disease, but it is more difficult to specify the cause. Generally there is a local primary disease in the anus that becomes secondary pruritus, otherwise it is primary pruritus. In addition, a general physical examination should be performed, and the necessary laboratory tests should be targeted, such as blood, urine, stool routine, liver and kidney function, urine sugar, blood glucose, glucose tolerance test and biopsy and smear.
1. Treat the primary disease or comorbidities, such as hemorrhoids, anal fistula, pinworm disease, etc. Give appropriate antibiotics or antimicrobials to treat co-infections.
2, avoid inappropriate self-treatment, many anal pruritus patients are reluctant to go to the hospital, take improper self-treatment, such as scalding with hot water, external use of high concentrations of corticosteroids or containing anti-irritant drugs, the purchase of some crude home physiotherapy equipment self-treatment, these methods are harmful, only temporary suppression of itching, over time, resulting in the lesion to extend the increase, patients should be advised to stop using.
3, pay attention to hygiene, do not eat or eat less irritating food, such as spicy food, strong tea and coffee, strong wine, etc.. Clothing and pants should be loose fitting, close underwear to cotton fabric is good.
4, limited anal pruritus drug treatment should be based on local topical treatment, systemic treatment of various types of agents used, such as corticosteroids, anti-inflammatory mediators, a variety of sedatives and other anal pruritus does not have a significant anti-itch effect, but there are many side effects or adverse effects, in the absence of clear indications should avoid the application.
5, only local itching and anal skin normal, to 4% boric acid water cleaning cold anal compress, if the addition of ice so that the water temperature at about 4 to 5 ℃ cold compress. Patients squatting with gauze or skim cotton cold compress anal, can be received immediately to stop the itching effect. Once a day, once in the morning and once in the evening, each time about 5min, after the cold compress with a dry towel to wipe dry the local, puffed with ordinary talcum powder, keep dry. This type of anal itch should not be applied externally ointment, ointment hinders heat dissipation, increased sweat prone to induce itching. It is advisable to use cool and dry lotions, such as white lotion, furnace glycerine lotion, etc.
6, the anal skin is rough and thick tessellation damage more often have a combination of infection, available appropriate antibiotics or antibacterial agents, infection control, the implementation of local encapsulation treatment; after cleaning the local, with alcohol or Neosporin solution local disinfection, with injectable prednisolone injection or de-inflammatory pine injection to injection needle drops of the drug in the lesion, so that the lesion is fully immersed in the drug, the patient feel itching reduced, local drug solution The patient feels that the itching is reduced and the local solution is dried, and then apply common rubber cream or ointment containing anti-itching agent according to the size of the lesion, or use film-forming agent or gel containing the drug as a film-like package. This method should be performed at bedtime, and after 6-8 hours, remove the hard paste or film-forming encapsulation, clean the area, and apply a drying lotion or anti-itch aerosol spray. This method has a good effect on relieving itching and prompting tinea infection damage to subside.
7.Injection therapy: The drug is injected into the subcutaneous or intradermal area to destroy the sensory nerves, causing local sensation to diminish, symptoms to disappear, and local damage to heal, which can be permanently cured in about 50% or more of cases. However, those with strict itching are prone to recurrence and need to be treated by injection again. Injecting drugs not only destroy sensory nerves but also motor nerves, which often lead to different degrees of sensory anal incontinence and sphincter malfunction, but can recover on their own after a period of time.
(1) Alcohol subcutaneous injection: Alcohol can dissolve the nerve myelin sheath without damaging the nerve axis, causing denaturation of sensory nerve endings and loss of sensation in the skin until the nerve regenerates, and there are two methods of injection. (1) Zonal subcutaneous injection method: Divide the area around the anus into 4 zones, and inject 1 zone each time. After skin disinfection, inject 5-10 ml of 1% or 2% procaine solution subcutaneously with a long needle, leaving the needle in place, and then inject 5-10 ml of 95% alcohol, the injected drug should be evenly distributed and not outflowed or under tension. Do not inject into the skin to avoid skin necrosis, and do not inject into the anal sphincter to prevent paralysis of the sphincter. After injection, apply hot compresses and give sedatives to relieve pain, and then inject another 1 area at an interval of 5-10 d. The 4 areas will be completely injected. (2) Multiple subcutaneous injection method: After local anesthesia, use a very fine needle to inject 3-10 ml of 95% alcohol into the subcutaneous area around the anus via multiple punctures, at a distance of 0.5 cm each, and inject 2-3 drops each, avoiding injection into the skin or sphincter.
(2) Methylene blue intradermal injection: inject 0.2% methylene blue solution into the perianal skin to make the sensation of internal nerve endings disappear and the itching subside, the injection solution is made of 0.2g methylene blue and 0.5g procaine dissolved in 100ml distilled water, the skin of the anus is coated with red mercury solution, the solution is injected into the perianal skin with a fine needle, 3~4 drops are injected at each place, and all the itching area is injected. The total amount should not exceed 20ml, and after the injection, the anus should be reapplied with sterile gauze and pain relief with morphine or codeine.
8.Surgical treatment
If the itching does not improve after the above treatment or recurs several times, surgery can be used. There are two kinds of surgical methods: removing the skin innervation of the anus and removing the skin of the anus.
(1) Subcutaneous incision: A semicircular incision is made on both sides of the anus, 5 cm from the anal verge, and the subcutaneous fat is cut, the skin is separated medially to reveal the lower edge of the external sphincter, and the skin is separated from the internal sphincter to the anal flap plane. Then the skin on the anterior and posterior sides of the anus was separated by deep tissue to allow for wound traffic on both sides of the anus. Finally, the skin at the outer edge of the incision is separated outward for 1 to 2 cm, and after hemostasis, the skin pieces are sutured in place, sometimes requiring drainage to be placed and covered with an external compression dressing. The bowel needs to be prepared before surgery, and fecal evacuation is controlled for 3 to 4 days after surgery. Effectiveness, reports vary, most achieve good results, but there are reports of recurrent cases and wound infection and dehiscence.
(2) Excisional suture: make an incision along the anal margin from front to back, make another curved incision on the outside of the incision, include the lesioned skin in the incision, connect the two ends of the incision, excise the semilunar skin between the 2 incisions, and suture the wound. The contralateral side was excised in the same way. Itching can be stopped after excision of the skin, but infection sometimes occurs in the wound.