Anal assault constitutes a significant proportion of all injuries resulting from childhood sexual abuse. In a recent review of 310 childhood victims of sexual abuse, abnormalities of the anus were identified in 104 children (34%). These included gaping of the anus (61 children), anal tags (44), anal fissures (33), sphincter rupture (15), condylomata acuminata (4), scarring (2), and bites (1).

Other findings that are consistent with chronic anal penetration include anal vascular congestion, hemorrhoids, anal skin thickening, erythema and hyperpigmentation, and shortening of the anal canal. An understanding of the normal appearance and size of the anal aperture is important, as is an understanding of other conditions that cause anal relaxation.

These latter include meningomyelocele, repair for Hirschsprung disease or imperforate anus, neuromotor conditions such as myotonic dystrophy, and inflammatory bowel disease.

A recent survey of children with chronic constipation attending a gastroenterology clinic indicated that anal relaxation is a rare finding in retentive constipation. Observation of the anus is best performed in the left lateral position with gentle lateral traction on the buttocks, and measurements should be made only after allowing approximately 30 seconds for relaxation to occur.

Anogenital infections may or may not be a sign of sexual abuse. Anogenital infection with human papillomavirus may be acquired either at birth or postnatally from an infected mother. Specific typing of the virus in both the patient and caregiver may clarify the source of infection.

The older the child is when genital warts appear, the higher the likelihood that they are acquired via sexual contact. Herpetic lesions may be spread from an infected caretaker or by autoinoculation from oral lesions. The simultaneous presence of anogenital warts or herpetic lesions with other sexually transmitted infections (eg, Trichomonas, gonorrhea, syphilis, Chlamydia) or physical signs of abuse increase the likelihood that sexual abuse is the cause.

Perianal rashes should be cultured for sexually transmitted organisms if the history is suggestive or the rash is unresponsive to standard therapy. Several reports stress how important full evaluation of perianal rashes is to avoid overdiagnosis of sexual abuse. Examples of conditions that have been mistaken for sexual abuse because of their presentation as perianal rash include molluscum contagiosum, pemphigus, lichen sclerosus et atrophicus, psoriasis, inflammatory bowel disease, perianal Streptococcus, and anal stenosis.

Mark Lane Welton, MD

References
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