Pôster:

SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis and osteitis) is rare in pediatrics and may mimic other clinical conditions. The course is usually prolonged, with periods of exacerbation and remission. It presents frequent axial skeleton involvement, resembling in part with spondyloarthritis, but also with neoplasias and osteoarticular infections (spondylodiscitis, osteomyelitis and Pott's disease). Diagnosis is based on clinical-radiographic and histopathological data, and treatment on non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids and disease-modifying antirheumatic drugs.

Case report

R.V.S, four-year-old girl, started three months from admission with painful palmoplantar vesicular lesions, which progressed to pustules, partially improving after topical antibiotics. One month later, she presented left hip inflammatory arthritis, extending to the lumbar, dorsal and cervical spine, with walking and seating difficulty, without improvement with NSAIDs. She also mentionated nighttime awakening and weight loss, with no fever, abdominal pain or diarrhea. Physical examination: erythematous and scaly palmoplantar lesions, with periungual hyperemia, nail dystrophy and onycholysis; difuse pain on spine palpation and mobilization, bilateral hip arthritis and positive tests for sacroiliitis. Initial investigation revealed high inflammatory markers, ANA, RF and HLA-B27 negative, and no evidence of neoplasia. Pelvic MRI showed foci of osteitis in the pubis, major left trochanter, sacrum and iliac margin of the left sacroiliac joint. Thoracic and lumbosacral MRI revealed a sign alteration compromising vertebral bodies of T1, T3, T7, T8, T9, T12 and upper and lower endplates of the lumbar vertebrae, as well as mild synovitis in lumbar interapophyseal joints. Because of the predominantly axial osteoarticular manifestations and suggestive skin changes, SAPHO syndrome was considered. It was initiated methotrexate (0.6 mg/kg/week) and prednisone (1.0 mg/kg/day) with complete resolution of pain and partial of skin lesios after two months. The dose of methotrexate increased to 0.9 mg/kg/week and the corticoid was withdrawn after three months, with complete clinical and laboratory resolution. Currently asymptomatic after six months with methotrexate monotherapy.

Conclusion

Despite its rarity, SAPHO should be considered in the presence of cutaneous and inflammatory osteoarticular manifestations, mainly of axial skeleton, even in the absence of histopathological confirmation. The good response to methotrexate in the present case, a safe medication, easy to access and used in a great proportion of rheumatic diseases, in addition to the current monocyclic disease course, suggests its use as a first line medication in the SAPHO management.