Aims: To determine the prevalence of HS in a population of children with CP, and to compare demographic and other features of children with both HS and CP, to those with only HS.

Setting: The Pediatric Rheumatology Clinic, Children's Hospital at Strong, University of Rochester Medical Center is staffed by 2 pediatric rheumatologists with approximately 500 patient visits/year.

Methods: Medical records of all patients seen in the Clinic between 1992 and 1997 and diagnosed with HS and/or CP were reviewed for: confirmation of diagnosis, demographic characteristics, time from symptom onset to clinic referral, and number (out of 5) of hypermobile joints. Diagnostic criteria for HS and CP were as described in the literature.

Results: There were 21 children with CP (13 female, 8 male; mean age at diagnosis=11.8±3.1 years) who were referred a mean of 15.5±5.7 months after symptom onset and represented 3.8% of the clinic population. Children with HS were much more frequently seen (N=81, 13.9% of clinic population) and were found to have the same gender distribution (51 female, 30 male) as those with CP. Their age at diagnosis was younger(8.4±3.9 years), but time from symptom onset to referral was longer(21.1±8.3months). Six, or 28.6% of those with CP also had HS, with characteristics of age (11.4±4.5 years) and time until referral(14.5±11.4 months) more similar to the CP than the HS population. The degree of hypermobility was greater in the combined group (CP & HS) than in the HS only patients, with 4 or more joints affected in 83% of the former but only 49% of the latter.

Conclusions: Though represented by a relatively small number of children, the proportion of patients with CP who also had HS was greater than the proportion of the overall clinic population with HS (28.6% vs. 13.9%). Those with both diagnoses were also found to have a greater degree of hypermobility than those with HS alone. Time until referral of children with both CP and HS was shorter than that of HS only patients, suggesting that greater symptom intensity in the former precipitated earlier rheumatologic consultation. Thus CP may be secondary, in some, to the laxity of hypermobility thereby placing it in the category of congenital diseases. It is analogous (at the lower end of the age spectrum) to the higher frequency of osteoarthritis seen in older individuals with HS.