Clinical characteristics of pediatric patients with acne fulminans associated to chronic non-bacterial osteomyelitis.
OBJECTIVE
Acne fulminans (AF) is a rare, explosive systemic form of acne. Chronic non-bacterial osteomyelitis (CNO) or chronic recurrent multifocal osteomyelitis (CRMO) is a primarily pediatric autoinflammatory disorder characterized by sterile osteolytic bone lesions. Concomitant occurrence of CNO/CRMO and AF is very rare and little is known about the epidemiological and clinical particularities of this association. The aim of this retrospective observational study was to describe the characteristics of pediatric patients with CNO/CRMO associated to AF.


METHODS
Electronic mailing lists of French medical societies were used to call for patients with CNO/CRMO and AF. A search for published patients with CNO/CRMO and AF was performed by screening PubMed.


RESULTS
We identified 5 original patients and 10 patients from the literature. All patients were adolescent boys. Mean age at disease onset was 14.9 years. 9/15 patients had received isotretinoin before the sudden onset of AF. Osteoarticular symptoms appeared within less than 1-3 months after the onset of AF. The mean numbers of clinical and radiological bone lesions were 3.6 and 5.6. The percentages of patients with involvement of vertebrae, pelvis, chest and cranial were 40%, 40%, 30%, 6.6%. Arthritis was observed in 69.2% of patients and sacroiliac arthritis in 46.2%.


CONCLUSION
CNO/CRMO associated to AF occurs predominantly in male adolescents and is characterized by frequent involvement of the axial skeleton and arthritis. Epidemiological and clinical features of these patients differ from general CNO/CRMO cohorts. Clinical management requires careful handling of isotretinoin doses.