Anal Pain: Office Diagnosis and Treatment

Patients almost always believe that their anorectal problems are caused by hemorrhoids, regardless of the nature of their symptoms. They frequently phone and ask us to prescribe a medication for their "painful hemorrhoids," and they are often dismayed when we insist that they must come to the office for an examination before we can prescribe any treatment.

While it is certainly understandable that our patients should make such an assumption, it is all the more important for us, as health care providers, to remember that anal pain frequently has a nonhemorrhoidal cause. In fact, 95% of patients who complain of anal pain have one of the following 3 conditions: anal fissure, thrombosed hemorrhoid, or anorectal abscess. In this article, we discuss the diagnosis and treatment of these conditions, as well as other, less common causes of anal pain.

FISSURE
An anal fissure is simply a tear in the anoderm. In men and most women, the tear, or ulcer, occurs very close to the posterior midline of the anal canal. The linear injury is typically caused initially by the passage of a hard stool, resulting in pain with defecation that can be accompanied by bleeding. The pain causes sphincter spasm and anal hypertonia, and thus begins a vicious circle of pain, spasm, and constipation. This syndrome is associated with relative ischemia of the posterior midline of the anal canal, an area with a relative paucity of blood vessels.¹

Often by the time patients arrange an appointment, what started as a tear has become an ischemic ulceration. At this point, the adjacent perianal skin may be edematous, forming a "sentinel pile"—the hallmark of a chronic fissure that will likely need surgical treatment. This swollen epithelial tag may resemble an external hemorrhoid. The anal papilla at the cephalad edge of the anal fissure may also become enlarged and hypertrophied as a result of the chronic inflammation. Thus, the classic triad of a chronic anal fissure is the fissure itself, accompanied above by a hypertrophied anal papilla and below by a sentinel skin tag.

Diagnosis. You can easily diagnose an anal fissure by carefully spreading the buttocks apart and observing the linear ulceration in the anal canal. At this point, further examination of the anorectum with either a finger or instrument is unnecessary and can be quite painful for your patient. Up to 10% of fissures occur in the anterior midline (particularly in women). Fissures that are not close to the midline suggest other processes that could result in anal or perianal ulceration, such as Crohn disease, syphilis, herpes, and carcinoma.

Treatment. Your patient may well express some anxiety about the pain and bleeding associated with an acute anal fissure. For this reason, reassurance is beneficial—emphasize that most fissures heal spontaneously with nonoperative treatment. Standard treatment includes stool softeners, such as methylcellulose or dietary fiber. Warm sitz baths seem to provide comfort and may relax the anal spasm and provide gentle anal cleansing following bowel movements.

Topical therapy. Topical corticosteroids and suppositories are ineffective and should be avoided; topical anesthetics are popular, but we do not routinely recommend their use to our patients. Because ischemia has been implicated in the propagation of a chronic fissure, several topical smooth muscle relaxants have been shown to be effective, probably by both lowering resting anal pressure and promoting vasodilatation. We find that topical diltiazem (2% gel) may relieve the pain and spasm and promotes healing. Topical nitroglycerin (0.2% cream applied twice daily) has been used with success; however, we have found that recurrence is common and patients often complain of headaches that accompany its use.

When surgery is needed. If the fissure does not heal or if the pain does not diminish substantially over the next 2 to 3 weeks, a more aggressive approach is justified. In addition, the presence of a sentinel pile and a hypertrophied anal papilla implies that the fissure is a chronic problem that is unlikely to respond to nonsurgical treatments (Figure 1).

The internal anal sphincter resides immediately beneath the anoderm and thus actually forms the base of a deep fissure. The internal sphincter becomes relatively rigid in a patient with a chronic anal fissure, a condition that seems to be associated with fibrosis of a portion of the sphincter. This rigidity of a portion of the internal sphincter can be appreciated by digital examination of the anal canal, but the pain associated with the fissure usually mandates that a local anesthetic be administered before such an examination. Relief of this rigidity is provided by internal anal sphincterotomy, a procedure that is nearly always curative.