produces a brief burning sensation that inhibits the urge to scratch. Lysy and col­leagues conducted a double-blind, random order, placebo-controlled, crossover study of topical capsaicin (0.006 %) and a placebo (1 % menthol) in 44 patients with severe intractable idiopathic pruritus ani for an at least 3-month duration, in which all patients received the study medication and the placebo three times a day for 4 weeks each, with the two study periods separated by a 1 week “washout” interval. Thirty-one (70 %) patients obtained symptom relief only from the capsaicin, not the placebo; in these patients, the itching score signifi cantly decreased following treat­ment with capsaicin ( p < 0.001) [ 10 ]. Notably, 24 of the patients who responded to capsaicin did so immediately, while the remaining seven patients experienced the benefi t within 3 days of instituting the medication [ 10 ]. Of the 13 nonresponders to capsaicin, 4 left the study due to side effects—moderate to severe perianal burning ( n = 3) and urticaria ( n = 1)—and one experienced an equal response to both medica- tions [ 10 ]. However, the authors note that all of the patients developed at least mild perianal burning as a consequence of applying the capsaicin, signifi cantly more so than after using the 1 % menthol ( p < 0.001); the subjects reported a signifi cant decrease in the capsaicin-induced perianal burning over the 4 weeks ( p < 0.001) [ 10 ]. For the 18 capsaicin-responsive patients who were followed for more than 8 months (range, 10–20 months), 4 were asymptomatic and 14 “nearly asymptom­atic” on a maintenance regimen of once daily capsaicin every 1.97 days (range,

The patient is a 26-year-old female with a history of asthma who presents to your offi ce, complaining of perianal itching for the past 4 weeks. The itching begins after her once-a-day bowel movement and continues until she goes to sleep at night. She applies an over-the-counter “hemorrhoid” cream, which initially seemed to relieve her symptoms, twice a day; the itching has instead been steadily worsening, encom­passing more of the perianal skin and even preventing sleep. She scratches fre­quently. She reports no other symptoms. On examination, the perianal skin is circumferentially erythematous, with excoriation, maceration, and vesicles noted. She has no other skin lesions or anorectal fi ndings.

The patient is a 60-year-old healthy male with a 5-year history of chronic pruritus ani, previously treated with conservative measures, various topical steroid prepara­tions, and rubber band ligation, who presents with persistence of the perianal itch­ing. A thorough investigation by his colorectal surgeon and dermatologist has uncovered no further anorectal pathology or perianal skin disorder. His recent colo­noscopy revealed only mild sigmoid diverticulosis. He seeks further treatment for the near-debilitating itching.

cryotherapy with liquid nitrogen spray; ultraviolet phototherapy; irradiation; surgi­cal denervation or excision (Clover Leaf procedure) of the perianal skin; and the injection of anesthetic agents, mercury sulfi de, phenol, or alcohol into the affected site have proven ineffective, too invasive, and/or too fraught with complications to be accepted into common practice [ 17 , 21 , 43 , 44 ]. First introduced in 1968, the injection of methylene blue has been demonstrated in small series to produce some benefi t in this diffi cult population of patients [ 45 ]. The treatment should be consid- ered in patients who are refractory to other measures, have become steroid depen­dent, or who have a poor quality of life due to the perianal pruritus. However, the patient should complain specifi cally of itching to profi t from the procedure: Eusebio and colleagues reported that their two patients with perianal burning or “irrita­tion”—not itching—showed no response to the injection [ 45 ]. Also methylene blue is contraindicated in patients with glucose-6-phosphate dehydrogenase defi ciency due to the association with hemolytic anemia [ 46 ]. The methylene blue is thought to destroy nerve endings, a fi nding that was confi rmed by electron microscopy of punch biopsy specimens taken 1 and 7 years after treatment [ 45 ]. In order to verify the therapeutic effect of the methylene blue, Mentes et al. treated six patients only with 0.5 % lidocaine, omitting the methylene blue; all of these patients experienced a recurrence of pruritus ani within a few days of the injection [ 17 ]. The protocols for the procedure vary among groups (Table 7.7 ). Most groups use a 22 or 25 gauge needle to inject 10–30 mL of 0.5–1 % methylene blue, producing a fi nal concentra­tion of 0.25–1 %, along with additives such as a local anesthetic (0.25 % Marcaine with 1:200,000 epinephrine, 2 % procaine, or 0.5 % Xylocaine) and steroid (meth­ylprednisolone or hydrocortisone). The medication was injected either subcutane­ously, intracutaneously, or intradermally. Sutherland and colleagues specifi ed their technique: “aliquots were injected intradermally to raise 10–15 mm blebs abutting each other.” [ 16 ] The procedure is usually outpatient, although Sutherland et al. admitted their patients for an overnight stay for patient-controlled analgesia. The short-term cure rates range from 65 to 100 % (Table 7.8 ). Some authors have retreated their patients shortly after their initial injection in the event of a partial or no response, with good results in 88 %. Mentes and colleagues increased the per­centage of symptom-free patients from 80 to 93.3 % by reinjecting the fi ve patients who were partial responders at 1 month postinjection; four patients had a complete response afterward. The success rate of the procedure has been shown to decrease with longer follow-up: Mentes et al. recorded that 93.3, 83.3, and 76.6 % of their patients were symptom-free at 1, 6, and 12 months after the procedure, respectively. After a median of 47 months of follow-up, only 20 % of the patients in the series from Samalavicius and colleagues were symptom-free [ 47 ]. Botterill and Sagar cor­relate the effi cacy of the procedure with persistence of the perianal tattoo for 2–6 weeks: the three patients who had no response lost the blue discoloration prior to 2 weeks, indicating that the dye was injected too deep [ 48 ]. Notably, Mentes et al. comment that three of the fi ve patients who developed recurrent symptoms at the 1 year follow-up were those who had required a second injection of methylene blue for symptom relief [ 17 ]. The authors speculate that patients who experience a much later recurrence may benefi t from reinjection of methylene blue [ 17 ]. In the series

The injection of methylene blue is associated with possible side effects that should be reviewed with the patient. The urine may briefl y appear blue-green due to excretion via the kidneys. The perianal area usually becomes hypoesthetic, which may persist from 4 weeks to 5 years. Patients may be insensate to pinprick for a longer period. The blue tattooing of the perianal skin may remain for 2–6 weeks. Urinary retention is a rare complication. Transient fecal incontinence has been reported. In the series from Sutherland and colleagues, 14 % of the patients experi­enced an impairment in continence, four to fl atus and three to stool, which resolved by 4–6 weeks and 10 days to 2 weeks, respectively; the authors attributed this com­plication to the migration of the dye to the anal canal, where it impacted sensation and, thus, continence [ 16 ]. However, Samalavicius et al., who purposefully directed the injection up to the level of the dentate line, recorded no changes in continence.

Skin necrosis was also identifi ed as a complication of the injection of methylene blue into the perianal skin. In the series from Eusebio and colleagues, 13 % of their patients developed full-thickness skin necrosis of up to 3 cm in diameter; after debridement, the sites healed within 8 weeks [ 45 ]. The authors comment that using the full concentration of methylene blue may have been the source of this complica­tion [ 45 ]. Others have pointed to the high volume of the injected fl uid—20 to 40 mL—as a source of the skin necrosis. Later studies, including a follow-up study from Eusebio, in which smaller volumes and a lower concentration were utilized, have not produced this same complication. Mentes et al. suggest that, even if a smaller volume risks not addressing the entirety of the affected perianal skin, it is more prudent to plan a second injection on a separate occasion [ 17 ]. Also, a too- shallow injection performed may risk skin ulceration [ 17 ].

The patient is a 35-year-old G2P2 female with a history of rubber band ligation due to grade I internal hemorrhoids following the birth of her fi rst child, who presents with a 4-month history of bright red blood on the toilet paper, discomfort and swell­ing of the anus, and perianal itching after bowel movements. A thorough history and physical examination are performed. The anoscopy demonstrates internal

hemorrhoids that prolapse but spontaneously reduce (grade II) and perianal excoria­tion with mild erythema.