Persistent and disabling fatigue associated with low-grade fever and other constitutional symptoms, without any known disorder that accounts for it, is recognized as chronic fatigue syndrome (CFS). Skin lesions occur in 10–35% of patients, but their description is inaccurate. Recurrent aphthous stomatitis or persistent Epstein-Barr virus (EBV)-related erythema multiforme have also been reported. Patients may be diagnosed as having CFS only when they fulfill at least 2 major and 8 minor criteria. Major criteria are the presence of debilitating fatigue persisting or recurring for at least 6 months and the absence of any other medical disorder that may explain it. Although different viral or nonviral etiologies have been documented, evidence implicating EBV is gaining suppor