Differentials
Crohn's disease
SIGNS / SYMPTOMS
History of Crohn's disease.
Abnormal-looking perianal skin.
Presence of anal fistulae, lateral site of fissure.
Painless fissure (in 50%).
Other symptoms and signs include abdominal pain and prolonged diarrhea. May also present with bowel obstruction, fever, fatigue, abdominal tenderness, weight loss, oral lesions, abdominal mass, extraintestinal manifestations (e.g., erythema nodosum or pyoderma gangrenosum).
INVESTIGATIONS
Upper gastrointestinal and small bowel series: edema and ulceration of the mucosa with luminal narrowing and strictures.
CT abdomen/MRI abdomen pelvis: skip lesions, bowel wall thickening, surrounding inflammation, abscess, fistulae.
Colonoscopy: aphthous ulcers, hyperemia, edema, cobblestoning, skip lesions.
Tissue biopsy: mucosal bowel biopsies demonstrate transmural involvement with noncaseating granulomas.
Sarcoidosis
SIGNS / SYMPTOMS
History of sarcoidosis.
Lateral site of fissure.
Other key symptoms and signs of the disease in other anatomic regions include cough, dyspnea, erythema nodosum, lupus pernio, chronic fatigue, arthralgia, wheezing, rhonchi, lymphadenopathy, photophobia, red painful eye, blurred vision, conjunctival nodules, facial palsy.
INVESTIGATIONS
Chest x-ray: hilar and/or paratracheal adenopathy with upper lobe predominant, bilateral infiltrates; pleural effusions (rare) and egg shell calcifications (very rare) may be seen.
Examination under anaesthetic and biopsy showing histopathological evidence of sarcoid with non-caseating granulomas.
Tuberculosis
SIGNS / SYMPTOMS
History of tuberculosis (TB).
Lateral site of fissure.
TB of the abdomen may also present with signs and symptoms including enlarged lymph nodes, abdominal swelling, abdominal pain, hepatomegaly, fever, weight loss of more than 10% body weight, anorexia, malaise, night sweats.
INVESTIGATIONS
Chest x-ray: may be evidence of unrecognised pulmonary TB or evidence of old healed TB (e.g. upper lobe fibrosis).
Examination under anaesthetic and biopsy showing histopathological evidence of TB; culture of tissue from fissure growing Bacterium tuberculosis.
HIV infection
SIGNS / SYMPTOMS
History of HIV.
Risk factors in history including needle sharing with IV drug use, unprotected receptive anal or unprotected receptive penile-vaginal sexual intercourse, percutaneous needle stick injury, high maternal viral load (mother-to-child transmission).
INVESTIGATIONS
Enzyme-linked immunosorbent assay, western blot, RNA test, or DNA polymerase chain reaction positive for HIV.
Lymphoma
SIGNS / SYMPTOMS
Lymphadenopathy elsewhere.
Night sweats, weight loss, fatigue/malaise, fever.
INVESTIGATIONS
Biopsy of enlarged lymph nodes.
Syphilis
SIGNS / SYMPTOMS
Unhealing fissure.
Risk factors in history include sexual contact with an infected person, men who have sex with men, illicit drug use, commercial sex workers, multiple sexual partners, people with HIV or other STIs, syphilis during pregnancy (risk for congenital syphilis).
INVESTIGATIONS
Serum tests positive for syphilis.
Anal carcinoma
SIGNS / SYMPTOMS
History of human papillomavirus infection.
Atypical site and shape of fissure.
INVESTIGATIONS
Examination under anaesthesia and biopsy showing squamous cell carcinoma.
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