Martial wrote in 1st century AD that “the favourite sexual use of children was not fellatio, but anal intercourse” [26]. Summit wrote “Manual, oral and anal containment of the penis are the “normal” activities of incestuous intercourse, as they are also for the more typically out of family sexual assault of boys” [27]. Anal signs were central in the Cleveland Inquiry [28] which recommended further study which in turn lead to publications by the Royal College of Physicians which provided guidance for clinicians [29, 30]. Allegations of anal abuse appear to be relatively rare, as these disclosed cases represented only 5% of all CSA cases seen. This possibly explains why the recent RCPCH review noted a serious lack of evidence on anal signs in children [4]. The resulting uncertainty has limited doctor’s ability to provide clear opinions.
Identification of a group where CSA can be confidently diagnosed or excluded is always challenging. While we cannot be certain that all the children who alleged anal abuse were true cases, it is generally accepted that disclosure is strongly indicative of abuse. Ideally the non abused controls would be sampled from the general population, but in practice recruiting a truly representative group and excluding CSA can be problematic. Selection of children from the general population has proved quite difficult, but it also raises serious ethical considerations. In one of the few studies of this kind [15] only 10% of parents approached participated and some later admitted that concerns that their child had been abused motivated them to participate. In that study perianal venous congestion was more commonly seen (16%) than in another study where 1% of younger children showed this sign [14].
A different approach was used in a recent study [11]. Children evaluated for possible sexual abuse were divided into 2 groups, one with a low probability (917 children) and one with a high probability (198 children) of having been anally penetrated. Comparison was made between these groups in terms of the physical signs observed. However identifying comparison children with a low risk of having been anally penetrated in a group of children referred for sexual abuse evaluation is problematic as suggested by the presence of anal bruising in 10, anal fissure in 25 and anal laceration in 3. Consequently, the solution of choosing as controls children examined with concerns about other forms of abuse where the routine practice was to include anal examination seemed overall the best solution to us.
While physically abused and neglected children have a known increased risk of CSA [31], in this study the fact that wide ranging sensitive information was available minimised the likelihood of including unrecognised CSA. However, it is possible that an occasional sexually abused child could unintentionally have been included in the control group and if so this would mean that the prevalence of signs seen in the controls would be overestimated. Control children with anal photographs were more likely to be included in this study than those without, and this could also have had the effect of overestimating the proportion of controls with positive findings. If this were the case that would imply that the true difference between groups was in fact even greater.
There were small differences in examiner status between cases and controls, cases were drawn over a longer time period than controls and the age range of cases and controls was slightly different, but statistical adjustment for all these factors made no meaningful difference to the results.
An important remaining concern is the possibility of examiner bias. When examining a child who has alleged anal abuse, a physician might be more confident in reporting abnormal findings than in a child with no such history. However both groups were examined by the same staff who would be alert to the possibility of undisclosed anal abuse and with experience of eliciting the signs in question. This makes it possible that examiners in this centre were more likely to detect signs in general, but this would apply to both cases and controls.
Thus while the limitations of the samples must be recognised, this remains the first case/control study in which a large group of children all of whom disclosed anal abuse was examined using the same techniques and examiners as controls, using well defined terminology. The difference in frequency of some signs between cases and controls suggest that they are likely to relate to abuse. In particular RAD and perianal venous congestion were seen frequently in cases, but rarely or not at all in controls. RAD is dramatic, involves dilatation of both sphincters, requiring observation for up to 30 seconds as it does not always appear immediately. Previous studies found RAD in 10% to 34% disclosing anal abuse and 5% to 20% reporting any sexual abuse (Table 5) [4]. In children selected for non-abuse, RAD was noted in 5% examined in the knee chest, but less than 1% in the left lateral position [16]. Another study [15] found none with the sign. An earlier study which has influenced practice especially in North America [17] described anal dilatation in 49% children selected for non-abuse examined in the knee chest position, for up to 8 minutes. But this position is rarely used in the UK. Apart from that study our figures for cases (22%) and controls (0%) lie within the range of other studies for both abused and “non-abused” in the left lateral position.
Anal laxity (reduced anal tone) was seen more commonly in our cases than in earlier studies [7, 12, 36], but had never been previously considered in children selected for non-abuse (Table 5). Anal fissure and laceration are injuries in the perianal skin. There is a lack of agreed definitions to fully differentiate them. Our figures which combine fissures with lacerations gave prevalence for both cases and controls which were within the range described in other studies (Table 5). Perianal venous congestion was at the upper end of the range for cases in previous studies and the lower end for controls (Table 5). As with most previous studies, anal bruising was uncommon following abuse and rarely reported in “non-abuse”. Erythema was seen more commonly than in previous studies probably reflecting a higher proportion examined soon after an assault than in previous studies.
Anal dilatation and venous congestion were so rarely seen in controls, that it raises the possibility that they should be recognised as signs which should prompt further investigation, as long as they are interpreted in the broad context of a detailed medical, social and family assessment and the child’s behaviour and demeanour.
The highest frequency of signs was seen in those abused less than 7 days previously and in those where the timing of the abusive episode was not known. But none of the signs were seen only within 7 days of the alleged assault, suggesting that examination is worthwhile even some weeks after the alleged assault.
The majority of cases had at least one sign, though in many these were non-specific. This observation is consistent with previous studies reviewed by the RCPCH [4]. Of seven studies reporting any abnormal signs, two found these in 61-95% [5, 35] and two in 46% and 57% [6, 33], despite widely differing methodology and definitions. However a quarter had no signs, so the absence of physical signs could not be said to negate a child’s history or exclude the possibility of abuse.
