1. Inflammatory dermatoses
3. Benign, premalignant and malignant dermatoses
Perianal dermatitis of the newborn
Lichen simplex chronicus
Lichen sclerosus et atrophicus
Miscellaneous inflammatory dermatoses
Other related conditions
Folliculitis and furunculosis
Streptococcal dermatitis/perianal cellulitis
Sexually transmitted diseases
Anal intraepithelial neoplasia (AIN)
Carcinoma of the anus
Extra-mammary Paget’s disease (EMPD)
4. Congenital and developmental abnormalities
5. Trauma in the perianal area
6. Chronic perianal pain
12.3 Inflammatory Dermatoses
Inflammation in the perianal area may result from the coexistence of several factors including hemorrhoids, anal discharge, proctitis, presence of fissures, or the effect of scratching. In all cases of perianal and perineal inflammation, the urine should be tested, and skin swabs and scrapings examined for organisms, especially tinea. Any irregularity of the bowels that causes straining or soiling should be evaluated and corrected.
12.3.1 Contact Dermatitis
Contact dermatitis in perianal region, one of the most common eczematous processes, can be either primary irritant or allergic.
Primary irritant contact dermatitis is caused by skin contact with an irritant resulting in inflammatory reaction in a previously non-sensitized individual. Irritant contact dermatitis is seen in infants as diaper dermatitis and in older patients as a consequence of overzealous cleanliness with detergents, irritation by stools as in urinary or fecal incontinence, chronic diarrhea, or bowel disease including tumors or inflammatory bowel disease, along with ingestion of spicy foods or cathartics (Odom et al. 2000).
Allergic contact dermatitis (ACD) is type IV delayed-type or cell-mediated hypersensitivity reaction occurring in a previously sensitized individual after repeated contact with the allergen. Allergic dermatitis can have many causes, mainly neomycin, “caine mix,” quinolines, lanolin, and ethylenediamine (Wilkinson et al. 1980). Other allergens include biocide preservatives and fragrances in moistened toilet tissue (Swinyer 1980; Van Ginkel and Rundervoort 1995; De Groot et al. 1991), lidocaine (Hardwick and King 1994), tetracaine (amethocaine) hydrochloride (Sanchez-Perez et al. 1998), local anesthetics used in topical antipruritics for piles (Lee 1998), and mitomycin C (Fisher 1991). The role of food allergy in causing perianal symptoms is debatable. Homosexual men may be susceptible to condom hypersensitivity (Fisher 1987).
The clinical presentation can vary, but typically there is erythema and varying degrees of edema, vesiculation, maceration, and oozing. Symptoms include pruritus and/or a burning sensation in the affected area. Diagnosis is based on detailed history taking, clinical examination, and patch testing for ACD. Treatment is mainly based on removal of irritant or allergen, topical or oral corticosteroids, symptomatic treatment with antihistamines, and hydrophobic barrier creams for long-term prevention of recurrences.
12.3.2 Danthron Contact Dermatitis
This is a form of irritant reaction to the use of danthron as a laxative (Barth et al. 1984). Danthron (1,8-dihydroxyanthroquinone) is reduced in the large bowel to active agent 1,8-dihydroxyanthron, which is chemically identical to dithranol, so causing “dithranol burn”-like reaction. There is a sharply demarcated erythema corresponding to the area of contact with feces. It is usually seen in Hirschsprung’s disease or encopresis and sometimes in elderly incontinent patients (Barth et al. 1984).
12.3.3 Perianal Dermatitis of the Newborn
Perianal dermatitis of newborn has been reported to have an overall incidence of 5–20 % (Hidano et al. 1986). The precise cause of perianal dermatitis in the newborn remains unknown, and it is assumed to represent an irritant response to fecal constituents. Generally erythema of the perianal skin makes its initial appearance during the first 8 days of life and is confined to 2–4 cm diameter zone around the anus (Pratt 1951). The affected skin may be edematous and superficially eroded in more severe cases. Perianal dermatitis may sometimes be associated with primary irritant napkin dermatitis or seborrheic dermatitis of infancy. Attention to hygiene, emollient application, and a protective lubricant are important in the management.
12.3.4 Seborrheic Dermatitis
Seborrheic dermatitis is a common eczematous process with a predilection for areas with abundant pilosebaceous glands, such as the scalp, nasolabial folds, and eyebrows, but can also occur in the perianal area. The etiology has not been fully elucidated, but possible association with the yeast Malassezia furfur is opined. It is a chronic condition characterized by pruritus and greasy scaling together with erythema, edema, vesiculation, maceration, and oozing of varying degrees, often bilateral and symmetric. Diagnosis is made mainly by clinical examination and less commonly through the histological findings on biopsy and response to treatment. Topical application of mild to moderate potency corticosteroids along with antifungals is usually all that is needed. Oral agents may be required in recalcitrant cases.
12.3.5 Atopic Dermatitis
Atopic dermatitis, the prototypical eczematous skin disease, may involve perianal region especially in children, although more common sites of involvement are the antecubital and popliteal fossae, face, neck, chest, and wrists. The hallmark of atopic dermatitis is pruritus, which leads to excoriations, with resultant scratching leading to subsequent development of chronic changes of lichenification and even scarring. Atopic dermatitis passes through acute (erythema, edema, vesiculation, and oozing), subacute (crusting, scaling), and chronic (hyperpigmentation, accentuation of skin lines, and skin thickening) stages, with secondary bacterial infection. Treatment is commonly based on proper moisturization, topical corticosteroid preparations, and oral antihistamines, but more severe cases can be treated with oral corticosteroids, ultraviolet light, and topical or oral immunosuppressants.
Psoriasis is chronic, inflammatory disease of the skin, characterized by erythematous plaques with hyperkeratosis, with the typical psoriasis plaque being well circumscribed, red, and scaly, topped by typically large, easily detachable, silver-toned scales (Fig. 12.1). Psoriasis of the anogenital region may look quite different from psoriasis at other sites. In the intergluteal fold, the plaques tend to be more humid and less scaly, with more maceration and fissuring. Silvery scales are rarely noticed on perianal lesions. Psoriasis in the perianal area may be difficult to treat.
Perianal and gluteal psoriasis
12.3.7 Lichen Simplex Chronicus
Lichen simplex chronicus in the perianal area appears as an area of lichenification usually unilateral, and localized to the edge of the anus in one site, and results from chronic, continuous scratching.
12.3.8 Lichen Sclerosus et Atrophicus
Lichen sclerosus is a chronic inflammatory disease that preferentially affects the anogenital region. Lichen sclerosus in the perianal area has very rarely been reported in males. In females, perianal area may be involved, along with vulva, with thin, wrinkled, atrophic skin, in a characteristic figure-of-eight distribution (Wallace 1971). Patients may present with pruritus, soreness/pain, dyspareunia, urinary or bowel symptoms, or asymptomatic. Lichen sclerosus is a scarring disease and some architectural change is common. The diagnosis is established by a combination of the characteristic clinical and histological findings. Complications include scarring and malignant transformation.
12.3.9 Hidradenitis Suppurativa
Hidradenitis suppurativa is a disease of the skin containing apocrine glands, especially the axillae, groin, and buttocks, along with perianal area. Pore occlusion of the apocrine glands leads to stasis, bacterial infection, and the resultant formation of characteristic tender, erythematous, hard nodules that may evolve into fluctuant interconnecting abscesses, which rupture leading to sinus tract formation, and multiple fistulous tracts.
Hidradenitis suppurativa may result in varying degrees of inflammation and scarring (Fig. 12.2). It is more common in black and Mediterranean individuals. In established hidradenitis, a variety of presentations may be found such as bridged comedones, folliculitis and furunculosis, deep burrowing discharging sinuses, nodules, cysts, fluctuant abscesses, scarring, and fibrosis (Coda and Ferri 1991). Urethral–cutaneous fistula and phimosis may occur (Chaikin et al. 1994).
Severe degrees of morbidity occur with interference with sitting, sleeping, walking, defecation, and sexual activity, which may lead to depression. Long-duration disease carries a significant risk of progression to squamous cell carcinoma (SCC) and rarely verrucous carcinoma (Black and Woods 1982; Cosman et al. 2000). Hidradenitis is usually a clinical diagnosis. Investigations include taking swabs for bacteriological evaluation and to guide therapy, evaluation for sexually transmitted diseases, and skin biopsy to exclude carcinoma or Crohn’s disease.
Treatment is challenging. Phenolization of small localized lesions and intralesional corticosteroids for early lesions may help. Marsupialization, diathermy destruction of the affected tissue, and carbon dioxide laser have been found to be effective (Brown et al. 1986; Finley and Ratz 1996). Silastic foam dressing may facilitate healing. Plastic surgery with complete excision of all the involved skin may be required. Medical management in the form of long-term antibiotic therapy (erythromycin, flucloxacillin, ciprofloxacin, metronidazole), oral prednisolone, and isotretinoin (1 mg/kg) for 6–8 months has proven helpful (Highet et al. 1988; Brown et al. 1988). Antiandrogen therapy and biologics such as infliximab and other TNF “biologicals” are being evaluated (Revoz 2009).
12.3.10 Crohn’s Disease (Synonym: Regional Ileitis)
Crohn’s disease is an inflammatory granulomatous disease of the gastrointestinal tract. Crohn’s disease can affect any part of the gut and perianal disease may occur in up to 75–90 % of patients (Markowitz et al. 1984). Perianal area may be involved by Crohn’s disease either by metastatic spread or by direct extension into the perianal region. Clinical features include those common to most chronic diarrheal illnesses, such as pruritus ani, skin maceration, and erosions with secondary infection.
Deep, undermined, angulated fissures with cyanotic edges and less commonly fistulae are common features, with multiple external openings encountered all over the perianal area and buttocks, scrotum, and thighs. Relative lack of pain, multiplicity of lesions, and eccentricity of fissures are important pointers for the diagnosis of Crohn’s disease (Alexander-Williams and Buchmann 1980). Any anal lesion in a patient who is known to be suffering from Crohn’s disease is likely to be perianal Crohn’s, and difficulty arises when anogenital disease represents the first manifestation. Diagnosis may be achieved based on symptoms, signs, and investigation results (e.g., radiography and biopsy) consistent with Crohn’s disease. Anal stenosis, fecal incontinence, and carcinoma are complications (Slater et al. 1984).
The differential diagnosis includes nonspecific anal fissures and fistulae, lesions of ulcerative colitis and diverticulitis (much less common), hidradenitis suppurativa, proctitis, perianal ulceration, abscess, fissure and fistula in homosexual men and those with HIV/AIDS, and pyoderma gangrenosum (Denis et al. 1992). Other differential diagnoses include sarcoidosis, schistosomiasis, leishmaniasis, tuberculosis, atypical mycobacterial infection, deep fungal infection, granuloma inguinale, lymphogranuloma venereum, chancroid, amoebiasis, syphilis and rarely condylomata acuminata, anorectal carcinoma, and other mucocutaneous malignancies (basal cell carcinoma, Kaposi’s sarcoma, and amelanotic malignant melanoma).
Management includes treatment of the underlying intestinal Crohn’s disease and local measures including soaks with potassium permanganate and aluminum acetate, potent or very potent topical corticosteroid/antibiotic combinations, and oral antibiotics (as for hidradenitis). A role has been advocated for long-term oral metronidazole (20 mg/kg/day in divided doses), sulfasalazine, prednisolone, and azathioprine (Bernstein et al. 1980; van Assche et al. 2009).
12.3.11 Miscellaneous Inflammatory Dermatoses
Acrodermatitis enteropathica presents with perianal eczematous dermatitis in the perianal area (Ecker and Schroeter 1978) (Fig. 12.3). Other deficiency diseases with some similarity to acrodermatitis enteropathica are pellagra, maple syrup urine disease, and neonatal citrullinemia.
Perianal involvement in acrodermatitis enteropathica
Radiodermatitis may result following previous treatment for in situ or frank carcinoma or pruritus ani.
Lichen planus (LP) involving perianal region may become excoriated or hypertrophic.
Fixed drug eruption and Stevens–Johnson syndrome may produce anal and perianal lesions.
Bullous disorders such as cicatricial pemphigoid, Hailey-Hailey disease, and epidermolysis bullosa (Fig. 12.4) may affect perianal skin and may cause anal stenosis.
Perianal involvement in epidermolysis bullosa
Behçet’s disease occasionally presents with multiple shallow ulcers and fissures of the anal margin. Behçet’s disease is a rare multisystem inflammatory disorder in which recurrent oral aphthae combine with some of the following clinical features: genital erosions or ulcers, arthritis, uveitis, neurologic disorders such as cranial nerve palsies and mono- and hemiparesis, arterial and venous thromboses, and pathergy.
Calciphylaxis sometimes affects the thighs and buttocks.
Primary systemic cutaneous anosacral amyloidosis has a predilection for the anogenital region, particularly the sacrum (Mukai et al. 1986).
12.3.12 Other Related Inflammatory Dermatoses
18.104.22.168 Anal Fissures
A true anal fissure is a midline linear perianal ulcer that is caused by defecation of hard stools causing pressure trauma and necrosis, or postoperative complications or idiopathic. Symptoms include intense pruritus, pain, bleeding, mucous discharge, and constipation. There may be a “sentinel pile” at the anal pole of the ulcer. Management is both medical and surgical.
22.214.171.124 Anal Fistula
Communication between the anal canal and the perianal skin is mostly found in the midline posteriorly, though there may be multiple openings (Fig. 12.5). Fistula may arise from infection/abscesses within the anal glands, Crohn’s disease, foreign body, and tuberculosis, to mention a few. Pruritus ani related to seropurulent discharge is the usual presentation along with pain resulting from abscess formation. Management is mainly surgical.
126.96.36.199 Pilonidal Cyst/Sinus
Perineal pilosebaceous unit and precursor pits associated with trapped hairs result in formation of pilonidal cyst/sinus (Millar 1970). Pilonidal sinus occurs in the midline, sacrococcygeal location being the most common site. It may present as a nodule or cyst, which ruptures and becomes infected. Symptoms include itching, pain, recurrent abscess, purulent discharge, and persistent nodule. Clinically, pilonidal sinus constitutes part of the “follicular–occlusion tetrad,” along with hidradenitis suppurativa, acne conglobata, and dissecting cellulitis of the scalp. Treatment is symptomatic and mainly surgical (Allen-Mersh 1990).
188.8.131.52 Pruritus Ani
Pruritus ani in itself is not a diagnosis, but a symptom complex having many causes; almost 50 % have a cause after dermatological evaluation (Jones 1992). It may be associated with various forms of anal diseases and with skin conditions involving the perianal area. Anal itching occurs in association with any inflammatory or eczematous condition of the perianal skin, anal fissures, anal fistulae, piles, skin tags, malignant tumors, mycotic infections, candidal infections, threadworm infestation, staphylococcal infection, folliculitis, erythrasma, warts, underlying skin diseases such as psoriasis, atopic dermatitis, lichen planus, lichen sclerosus, systemic disease pellagra, hypovitaminoses A and D, diabetes mellitus, and psychological and idiopathic factors (Harrington et al. 1992).
Various clinical features result secondary to the effects of rubbing, secondary infection, and contact dermatitis.
Common causative factor of pruritus ani is fecal contamination (Kocsard 1981) (Fig. 12.6), because of irritant potential and presence of potential allergens and endopeptidases of bacterial origin, capable of inducing itching in the presence of preexisting skin disease (e.g., seborrheic dermatitis or flexural psoriasis) or even in the absence of visible disease (Caplan 1966; Andersen et al. 1994). Anal leakage may result from coexisting anal disease, exaggerated recto-anal inhibitory reflex, or anal sphincter dysfunction (Allan et al. 1987; Eyers and Thompson 1979) or be precipitated by broad-spectrum antibiotics and diarrhea.
Flowchart showing pathogenesis of pruritus ani
The causes of fecal contamination include:
Difficulty in cleansing the area because of obesity, frequent defecation, and anatomical factors
Anal leakage because of hemorrhoids, perianal tags or fissures, and primary anal sphincter dysfunction.
Food and drink – uncertain, although compelling evidence
General measures include attention to the patient’s washing habits, suitable soap substitute; moisturizer after each wash; barrier preparation pre-applied to the perianal skin before the bowel opening; washing preferred to wiping with toilet paper; wearing loose cotton underwear; avoiding topical anesthetics; curtailing coffee consumption; excluding foods, such as nuts, that provoke the pruritus; and encouraging high-fiber diet (Alexander-Williams 1983). Local applications of mild topical corticosteroid/antibiotic/antifungal preparation are useful for acute episodes. Other treatments that have been advocated include zinc paste with 1–2 % phenol, half-strength Castellani’s paint, weak (0.05–0.25 %) silver nitrate solution, oral antihistamines, corticosteroid suppositories, systemic corticosteroids, and intralesional methylene blue, with or without Marcaine/epinephrine/xylocaine (Eusebio 1991). Concomitant diseases such as hemorrhoids, fissures, anal spasm, and occult mucosal prolapse should be treated. Lord’s stretch procedure has proved helpful (Ortiza et al. 1978) and above all reassurance.
12.4.1 Folliculitis and Furunculosis
The perianal area is susceptible to infection with Staphylococcus aureus, involvement commonly being in the form of furunculosis and abscesses (Fig. 12.7). High temperature, humidity, pressure, and friction encourage colonization by staphylococci (Felman and Kikitas 1980). The perineal area is an important site for carriage of staphylococci. In adults, the carriage rate is of the order of 13–22 %, and in neonates, it may be higher.
Furuncle in perianal area
12.4.2 Streptococcal Dermatitis/Perianal Cellulitis
Superficial bacterial infections of the perianal area present with pruritus, painful defecation, anal soreness and redness, and satellite pustulosis of the buttocks, and examination of the anus shows a pronounced, sharply demarcated, and boggy erythema and most commonly affects children younger than 10 years of age (Rehder et al. 1988). Rarely, there may be a systemic presentation with fever and rash (Vélez and Moreno 1999). Group A β-hemolytic streptococci is the usual cause, and rarely S. aureus, and communal bathing has been blamed for outbreaks. Diagnosis rests on clinical presentation, response to medication, and identification of bacteria through culturing of the lesion.
12.4.3 Perianal Abscess
Perianal/anorectal/ischiorectal abscess presents with painful swelling and suppuration, commonly complicated by anal fistula. The most likely cause is infection of the anal glands, but trauma (e.g., impacted fish bone), diabetes, and anal cancer predispose to its development.
12.4.4 Ecthyma Gangrenosum
Ecthyma gangrenosum in the perianal area, caused by gram-negative organisms (pseudomonas aeruginosa), occurs if the balance of the skin flora is grossly disturbed. Patients present with severe anal pain, anorectal ulceration, and septicemia, and the prognosis is poor (Givler 1969).
12.4.5 Necrotizing Infections
Perianal area may be affected by a number of severe gangrenous and necrotizing diseases, often as a complication of surgery and trauma. These conditions include clostridial and non-clostridial gangrene; streptococcal cellulitis and myositis; streptococcal toxic shock syndrome; synergistic necrotizing cellulitis; necrotizing fasciitis; Meleney’s progressive bacterial synergistic gangrene; synergistic gangrene; and Fournier’s gangrene (Bubrick and Hitchcock 1979; Oh et al. 1982; Flanigan et al. 1978).
The condition may present as a primary perirectal abscess in the perineum, with pain generally being the first symptom. Subsequently, distinct dusky red erythema and necrotized area may appear in affected tissue, with tenderness and extension to wider areas leading to fasciitis and myositis (Fig. 12.8). Crepitus is an important feature, as is the presence of a dark brown, turbid fluid without pus. Bad prognostic factors are patients with diabetes, leukemia, old age, and delay in treatment.
Necrotizing fasciitis in the perianal area
Early recognition along with immediate and aggressive treatment is essential. High-dosage broad-spectrum antibiotic therapy should be started till results of the culture and sensitivity are available. Rapid and extensive debridement of all affected tissue may be needed.
12.4.6 Common Mycoses
The yeast, candida albicans, causes candidal intertrigo, found between the gluteal folds and also perianal dermatitis, often precipitated by use of oral antibiotic agents, steroid use, and pregnancy. Perianal candidiasis presents with pruritus ani and a more localized erythema, around the anus. There is a bright red, glazed appearance, often with outlying small pustules. Diagnosis relies upon clinical findings and microscopic examination of scrapings with potassium hydroxide for hyphae/pseudo-hyphae.