11 Perianal Dermatologic Disease
Abstract
Patients’ perianal dermatologic conditions are initially seen with a variety of symptoms and macroscopic appearances. Perianal skin conditions may be classified as pruritic and nonpruritic. When no underlying cause for pruritus can be identified, the condition is termed “idiopathic pruritus ani,” the most common type. The dermatologist and the surgeon frequently work in concert. This chapter reviews the dermatologic conditions with emphasis on diagnosis and treatment from the surgeon’s perspective.
11.1 Introduction
Patients with primary perianal dermatologic conditions and secondary perianal involvement in systemic diseases are initially seen with a variety of symptoms and macroscopic appearances. Even though patients may have painful, friable, indurated, ulcerated, or raised skin lesions, their most frequent symptom is pruritus. 1 For practical purposes, the perianal skin conditions may be classified as pruritic and nonpruritic. When no underlying cause for pruritus can be identified, the condition is termed “idiopathic pruritus ani,” the most common type. Consequently, it serves as the basis for much of this discussion. In treating this group of conditions, the dermatologist and the surgeon frequently work in concert. The dermatologist, because of his or her visual training, is equipped to diagnose, scrape, culture, and prepare microscopic preparations and perform a biopsy in the office, and the surgeon is able to examine and culture and to perform a biopsy on anorectal pathology through anoscopes and proctoscopes. This chapter reviews the dermatologic conditions with emphasis on diagnosis and treatment from the surgeon’s perspective.
11.2 Pruritic Conditions
11.2.1 Idiopathic Pruritus Ani
Pruritus ani is an unpleasant cutaneous sensation characterized by varying degrees of itching. Men are affected more often than women in a ratio of 4:1. 1 Idiopathic forms of pruritus ani occur in approximately 50 to 90% of the cases. 2 , 3 The remaining cases of pruritus are symptomatic presentations of either localized or systemic diseases (e.g., hemorrhoids, diabetes), which are considered later in this chapter.
History
Symptoms, which usually start insidiously, are characterized by the occasional awareness of an uncomfortable perianal sensation. The anal skin is richly endowed with sensory nerves, but the perceptions of individual patients vary. Some patients feel an itch, whereas others sense burning. Often, the patient is more aware of the problem at night or in hot, humid weather, although this is not always the case. The itching also may be exaggerated by friction from clothing, wool, and perspiration; on the other hand, applying cool compresses counters irritation, and heat avoidance, mental distraction, and lubrication of the skin surface ease the itching. With time, the condition may progress to an unrelenting, intolerably tormenting, burning soreness compounded by the insurmountable urge to scratch, claw, and otherwise irritate the area in a futile effort to obtain relief. The severely afflicted patient is eventually exhausted, and a few have been driven to suicide as a means of obtaining relief.
The patient has usually resorted to self-treatment with over-the-counter medications. The patient often overtreats; so a first step for the physician is to stop the acute, contact dermatitis. Poor anal hygiene is often a contributing factor; therefore, questions about the patient’s cleansing habits may be important. Specific dietary ingredients and neurogenic, psychogenic, and idiosyncratic reactions with pruritus should be suspected whenever another factor is not readily identified (see specific causes below). 1 , 4 , 5 , 6 Since the diagnosis is made by exclusion, inquiries about diabetes, psoriasis, family history of atopic eczema, use of local topical medications, seborrhea on other sites on the body, children with similar itching reminiscent of pinworms, antibiotic use, vaginal discharge or infection, acholic stools, dark urine, or anal intercourse may establish the factor or factors responsible for the symptom.
Stress and anxiety may exaggerate pruritus ani. Often, personal factors in life are omitted by the patient. When taking a history, the physician may have to encourage the patient to “open up” and to express or consider factors that may be contributing to the discomfort. Common complaints revolve around family, work, and finances. 7 Laurent et al used the Mini-Mult personality test for psychological assessment of patients with idiopathic pruritus ani versus normal controls. They found that the mean hypomania and depression scales were greater and smaller, respectively, in the idiopathic pruritus group. However, the conclusion was that psychological factors are only predisposing factors. 8
Physical Findings
In the early stages of the condition, examination may reveal only minimal erythema and excoriations. As the symptoms progress, the perianal skin becomes thin, friable, tender, blistered, ulcerated, and “weeping” (▶ Fig. 11.1). In the later stages, the skin is raw, red, lichenified, and oozing or pale (▶ Fig. 11.2), with exaggeration of the radiating folds of anal skin. Often, a secondary bacterial or fungal infection is present. A clinical classification from Washington Hospital Center, Washington, DC, is based on the appearance of the skin. Stage 0 skin appears normal. Stage 1 skin is red and inflamed. Stage 2 has white lichenified skin. Stage 3 has lichenified skin as well as coarse ridges of skin and often ulcerations secondary to scratching.
Careful local anorectal examination may distinguish an inciting factor, but a detailed skin examination of the entire body may provide the diagnosis. Adjunctive laboratory and radiologic testing (e.g., determining blood glucose and electrolyte levels or performing a barium enema) may be required to diagnose a primary cause. If a treatment program is begun before the factors that may result in pruritus have been ruled out, a primary cause may be overlooked. Rather than decreasing the misery of the patient, this approach may cause the condition to become worse.
Physiologic Testing
Physiologic studies of patients with pruritus ani have been performed to determine whether disordered function is a causative factor. Manometry, compliance, sensation to rectal balloon, and perineal descent have been measured and were found to be the same as those of controls. 9 The exception was a significantly greater fall in anal pressure with rectal balloon distention. 2 , 9 Farouk et al 10 used computerized ambulatory electromyography and manometry to demonstrate that patients with pruritus ani have an abnormal transient internal sphincter relaxation, one that is greater and prolonged. Thus, occult fecal leakage with subsequent perianal itching results. Others have shown a decreased resting anal pressure by manometric comparison before and after coffee consumption. 4 Thus, coffee may contribute to a leak.
Saline infusion tests showed early leakage (after 600 mL) as compared to control subjects (after 1,300 mL). 9 There is an inverse relationship between the severity of symptoms and the volume of first leakage. Again, leaking and soiling seem to be major factors.
Histopathology
In acute pruritus, epithelial intercellular edema and vesiculation are present. In chronic cases, hyperkeratosis and acanthosis are noted. Atrophy of the outer layers of the epidermis, sebaceous glands, and hair follicles may occur, but in part this may be due to use of potent steroids. Finally, ulceration may supervene.
Treatment
Therapy for idiopathic pruritus ani is nonspecific and often involves changes over the course of time. The treatment is directed at regaining a clean, dry, and intact perianal skin. The following discussion outlines a broad approach to this symptom complex, including reassurance, education, local treatment, and follow-up.
Reassurance
Since, by definition, idiopathic pruritus ani has no identifiable primary cause, treatment is mainly symptomatic and directed toward decreasing moisture in the perianal area. Reassurance to the patient that there is no underlying pathology, particularly carcinoma, is often as effective in producing a “cure” as any of the physical or medicinal modalities used. Often, these patients have a long, protracted course of treatment, and a sympathetic, reassuring approach is necessary to achieve ultimate success.
Education and Local Treatment
Providing patient education is very important. Patients are instructed to cleanse several times daily, especially after bowel movements. Although cleanliness is stressed, the use of medicated soaps in the perianal region is discouraged. In the acute, excoriated, weeping, crusting stage, warm wet packs may aid in debridement. The patient can dry himself or herself gently with either a soft towel or, preferably, a hair dryer. A combination of Kerodex 71 and 2.5% hydrocortisone ointment is used as a barrier on the perianal skin and to reduce inflammation. Fluorinated steroid topical preparations should not be used over long periods of time because skin atrophy will ensue and perhaps incite a more unpleasant skin condition. Anesthetic preparations such as Xylocaine ointment may mask the disease or contribute to an allergic dermatitis; thus, the use of soothing topical medications is preferred. As the condition improves, or is in milder forms, creams and lotions are replaced with cornstarch powder or talc. A small wisp of absorbent cotton or absorbent paper tissue may be tucked into the anal cleft to help keep the area dry.
Coffee (including decaffeinated blends), tea, colas, chocolate, beer, citrus fruits, alcohol, dairy products, and tomatoes may contribute to idiopathic pruritus. 6 Serial elimination of each item for 2 weeks may help identify the offending substance. If the pruritus disappears, deleted foods are returned to the diet one at a time. If the pruritus recurs, the offending ingredient is withdrawn. Daniel et al 11 found that there is a direct correlation between the severity of perianal irritation and the amount of coffee consumed daily. If the patient has “after leak,” characterized by stinging, burning, or a perianal “crawling” sensation superimposed on the itch after a bowel movement, the patient is instructed to irrigate the rectal ampulla with a small tap-water enema. Following this procedure, the patient needs to cleanse the area with a wet tissue while straining down and opening the anal canal. This process is continued until there is no brown stain left on the tissue. A mucosal prolapse, a rectocele, or a hidden rectal prolapse might be suspected and observed during the physical examination.
Other nonspecific therapy includes shaving hirsute patients. However, as the hair grows back, the short stubble can be a source of irritation and increase the urge to scratch, defeating the original gains. Extreme cases may require sedation and/or antihistamines such as diphenhydramine hydrochloride (Benadryl), 25 mg, four to six times per day. Estrogens may be useful in postmenopausal women. Wearing loose-fitting clothes and undergarments made of cotton may be helpful. Softened fabrics have been shown to reduce frictional effect on skin, especially irritated skin. 12 Underwear made of synthetic fibers does not absorb perspiration. If a secondary bacterial or fungal infection is present, topical antibiotics or fungicides may be instituted based on the results from cultures and sensitivity testing. If medical therapy is failing, a biopsy to identify Bowen’s disease or Paget’s disease is in order.
In the past, various methods such as tattooing with mercury sulfide, sclerotherapy, radiation therapy, and surgical procedures have been used. These methods are generally condemned because permanent cure is seldom reported. However, Eusebio et al 13 treated 23 patients over a 9.5-year period with one intracutaneous injection treatment of the anodermal and perianal skin using intravenous sedation, local anesthesia, and up to 30 mL of 0.5% methylene blue. Of the 23 patients, 10 had complete long-term relief, 4 had complete relief but were lost to follow-up after 12 weeks, and 4 had relief for 12 weeks but experienced varying degrees of recurrence. The use of methylene blue was verified by Farouk and Lee 14 in six patients.
Follow-Up
Initially, patients with severe disease may need to be seen as frequently as twice per week. Providing reassurance and visible concern is often the most important part of therapy at this time. As symptoms improve, the time between visits can be gradually lengthened until the patient is seen once every 3 to 4 weeks. It is important not to discontinue seeing a patient using a steroid cream because chronic use can lead to the development of atrophic skin, superinfection, and a secondary pruritus or burning sensation.
Often, the symptoms wax and wane, and a cure is based more on a flexible therapy plan coupled with positive psychologic reinforcement than on the actual agent or agents used. Constant reiteration of the desired goals and the methods used to achieve them may be necessary. Finally, the physician should be willing to reassess the patient whenever there is any suggestion that a more specific entity may be responsible for the pruritus.
11.2.2 Primary Etiologies
Poor Hygiene
Poor hygiene is often associated with the diseases discussed in this section. Frequently, this is the only factor identified with cases labeled as “idiopathic.” The anatomy of a patient (e.g., a deep intergluteal cleft) may render the perianal region inaccessible to proper cleansing. In other cases, the patient is not fastidious in cleansing, and retained mucus, perspiration, and feces initiate the local irritation process. 4 Some disabled patients, such as those with arthritis, strokes, or multiple sclerosis, are physically incapable of performing adequate perianal hygiene. Likewise, the elderly who have even mild incontinence may not cleanse well, such that irritation and pruritus will ensue. 15
Anorectal Lesions
Any lesion in the gastrointestinal tract that can cause excessive moisture in the perianal region may result in pruritus. Hemorrhoids, anal fissures and fistulas, hypertrophied papillae, prolapse, and neoplasms are some of the more frequent anorectal offenders. Rubber band ligation often controls pruritus associated with hemorrhoids. 16 Treatment should be directed toward the specific pathology.
Infections
Infections can be caused by parasites, viruses, bacteria, fungi, or yeasts. These pathologies are considered in the following discussion.
Parasites
A common cause of perianal itching in children is infestation with Enterobius vermicularis, or pinworms. The child can be the source of infestation in the family. The worms emerge from the anal canal at night and early morning; consequently, pruritus is worst at those times. Scratching tends to scatter the eggs in the bed and wherever the patient disrobes. The diagnosis is made by microscopically identifying the E. vermicularis eggs or adult worms (▶ Fig. 11.3). The specimen is collected by applying clear, adhesive cellulose tape across the anus when symptoms are worst. The tape is then attached to a microscopic slide for examination. The use of lactophenol cotton blue stain enhances the detection of the colorless eggs. 17
If E. vermicularis is found, treatment consists of piperazine citrate (Antepar) in doses varied according to the patient’s age and weight or, preferably, mebendazole (Vermox), 100 mg for all ages, in a single dose. 18 Unfortunately, all family members must be treated because of the frequent cross-spread of eggs to family members. The eggs are everywhere in the household; therefore, after treatment, cleaning all floors, furniture, linens, and beds to eradicate the eggs is important to avoid reinfestation.
Pediculus pubis, a louse, is a parasite visible to the naked eye; under magnification, it resembles a crab (▶ Fig. 11.4). The nits of eggs embedded on the pubic hair can readily be observed. Treatment consists of malathion 0.5% lotion applied to the pubic and perianal hair and then rinsed off after at least 2 hours. An alternative is permethrin cream 1% applied and washed off after 10 minutes, carbaryl 1% applied and washed out 12 hours later, and phenothrin 0.2% applied and washed out 2 hours later. 19 A second application can be made a week later. 20 All sexual partners must be treated. Clothing and bedding can be sterilized by washing in very hot water.
Scabies is estimated to infect over 300,000,000 people worldwide. 21 It is a parasitic infestation characterized by itching on the arms, legs, and scrotum before the development of pruritus ani (▶ Fig. 11.5). 17 As the itch mite, Sarcoptes scabiei, burrows, it creates dark punctate lesions, which are readily identified on the trunk and particularly between the fingers and ventral surface of the wrists. The diagnosis depends on demonstration of the parasite in a potassium hydroxide preparation (▶ Fig. 11.6). Treatment includes topical application of 5% permethrin or 1% lindane (applied as creams or lotions from the neck down, and then washed off in 8–12 hours). 20 , 22 Oral ivermectin (150–200 mg/kg of body weight) given as an initial dose and again in 2 weeks cures 95%. Good hygiene and cleansing of all clothing and bedding by washing in hot water is necessary to avoid reinfestation. Some itching may persist for weeks, due to dead scabies parts, but mild topical steroids and systemic antihistamines control the itching. 23 In children, the head also must be treated. Care must be taken to avoid open wounds because absorption may cause convulsions.
Viruses
The most common viral infection in the perianal region is condyloma acuminatum, which is discussed in Chapter 12.
Perianal presentation of herpes simplex virus (HSV-2) is rare compared to its frequent presentation as genital infection (herpes genitalis) and even less frequently when compared to herpes simplex virus (HSV-1), which presents as the familiar “cold sore” and “fever blister.” The mode of infection is usually sexual, but the virus may be spread by direct contact from parent to infant or from the mouth and through the gastrointestinal tract to the perianal site. Unfortunately, HSV-1, the nasolabial cold sore type, is becoming a progressively larger proportion of the perineal herpes infections. 24
The incubation time is usually 2 to 7 days, but it may last up to 3 weeks, with prodromal symptoms consisting of minimal burning, irritation, or paresthesias. The infection is characterized by severe pain and pruritus, with a serous or purulent discharge. Tenesmus and secondary spasm are common. The pain may radiate to the groin, thighs, and buttocks.
The initial lesion is a small vesicle with a surrounding erythematous areola (▶ Fig. 11.7). Within 24 to 48 hours, the surface ruptures, and an ulcer results (▶ Fig. 11.8). In the immunosuppressed patient, ulcers may become confluent, appearing as ulcerating cellulitis. The lesions are distributed equally between the perianal skin and the anal canal. If the patient has never had a herpes infection, systemic symptoms (e.g., fever, chills, malaise) are common. Healing leaves scalloped scars. A recurrence may involve only some scattered vesicles.
The diagnosis usually is made by history and physical examination alone. Adjunctive methods include cytology, immunofluorescence, viral culture, and the Tzanck test. Currently, there are commercial companies vying for a faster, more accurate test, using the new glycoprotein G-based, type-specific HSV serologies. 25 If a vesicle or the margin of an ulcer is scraped, the scrapings may be smeared on a slide, heat fixed, stained with methylene blue, and rinsed. Multinucleated giant cells may be seen with this viral disease. Other viral diseases such as herpes zoster or chickenpox also have giant cells.
The disease is usually self-limiting in 1 to 3 weeks if there is no secondary bacterial infection. Symptomatic treatment (see discussion of idiopathic pruritus ani) is the basis for relief. Acyclovir may be used to abort the first attack. The usual dose is 400 mg five times per day for 10 days. 26 New antiviral agents, famciclovir 250 mg three times per day for 5 to 10 days and valacyclovir 1 g two times per day for 10 days, offer more convenient treatment schedules. 26 Recurrence is the rule, and acyclovir, valacyclovir, and famciclovir reduce the duration of viral shedding and time to lesion healing. 19 If recurrences are frequent, prescribing these drugs may be tried as prophylaxis. The prophylactic regimen is acyclovir 400 mg two times per day, valacyclovir 500 mg orally daily, or famciclovir 250 mg orally two times per day for 6 months. The immunosuppressed patient must be hospitalized for intravenous acyclovir treatment. 27 Steroids are never used because they may potentiate the infection. Other specific treatment such as immunization with vaccines has been shown to be largely ineffective in the treatment of genital herpes. 28
Lumbosacral dermatomes are involved in 11% of patients infected by herpes zoster. 29 The causative virus is Herpesvirus varicellae, which has a variable incubation period. The first manifestations are fever, pain, and malaise. After 3 to 4 days, the characteristic closely grouped red papules appear along dermatomes, and they become vesicular and pustular quickly. Lymphadenopathy is common.
Sacral herpes zoster may result in urinary retention and sensory loss in both the bladder and rectum. 29 These results can be seen even with unilateral skin involvement, which is somewhat perplexing since hemisection of the cord does not result in detectable sphincter dysfunction.
Treatment is mainly symptomatic. Oral acyclovir and steroids may give early relief and minimize neurologic sequelae. 29 Complete spontaneous recovery over 3 to 4 weeks is the usual course. Postherpetic neuralgia is the most common adverse sequela.
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