Table 5. Indications for clinical suspicion of SURF in children with recurrent fever [33–35]

Essential features
Recurrent fever: ≥ 3 episodes in 6 months; duration of 3–5 days
Exclusion of PFAPA, monogenic HRF and cyclic neutropenia
Asymptomatic interval between fever episodes
Normal growth and development

Additional features
Sore mouth, pharyngitis, or adenitis (i.e., PFAPA triad)
Respiratory symptoms ± past history of allergic diseases
Abdominal pain, nausea, or vomiting
Arthralgia or fatigue1)
Eye manifestations: Conjunctivitis or eyelid swelling
Response to treatment (e.g., steroids, colchicine, or anakinra)

Broderick et al.[34] reported that arthralgia and fatigue were less common than gastrointestinal symptoms.
SURF: syndrome of undifferentiated recurrent fever; PFAPA: periodic fever, aphthous stomatitis, pharyngitis, and adenitis; HRF: hereditary recurrent fever.