Genital abrasions may occur after accidental or self-inflicted trauma or following sexual assault. Dermatologic conditions with significant pruritus can also lead to abrasions and excoriations. Acute abrasions of the labia, perihymenal tissues, penis, scrotum, or perineum are considered moderately specific for abuse, but other causes should be considered as well.

Accidental injuries to the genitalia usually have a clear history, with findings on examination consistent with that history. Straddle injuries are a type of accidental trauma that lead to compression of the soft tissues of the vulva or of the penis between the object and the pubic ramus. These are usually associated with bruising, abrasions, and/or lacerations. In a typical straddle injury, one foot slips and the child falls downward, compressing the genital area (eg, on the monkey bars). This causes anteriorly placed abrasions and bruising of the genitalia. Scraping of the medial side of the thigh may also occur, especially if the object straddled has a rough surface (eg, the side of a swimming pool). Associated lacerations, if present, are most often superficial. In girls, the hymen is protected by the vulva and, therefore, should not be injured. Impaling injury may lead to hymenal trauma, usually with a corresponding clear history.

Stretch injuries, "the splits," can result in superficial lacerations in the skin of the perineum or fourchette, especially if there were preexistent labial adhesions or if it was a marked / forced anatomic abduction-type motion (eg, rollerblading injury).

Severe self-inflicted injury is unlikely because of the pain caused by self-trauma. Minor abrasions may occur if children scratch because of symptomatic vulvovaginitis or pinworm infection. Adolescents may cause minor injuries with masturbation.

Children with genital abrasions typically complain of genital pain, soreness, and sometimes dysuria when the urine passes over the abraded area. Often, there is associated erythema and/or ecchymosis. The urethral meatus may also have evidence of lacerations, erythema, and discharge. The external genitalia of boys must also be evaluated for abrasions and lacerations possibly due to a bite.

Perineal irritation, abrasion, and erythema are commonly caused by scratching due to the pruritus from contact dermatitis (often caused by diapers), seborrheic dermatitis, poor hygiene, and candidiasis.

Because positive physical findings of sexual abuse occur infrequently, one cannot overemphasize that the history from the child still remains the single most important diagnostic feature in assessing whether a child has been sexually abused.