Hi doctors, my son is 15 months now and he s been having fever for 5 days. His fever is up and down, mostly high in the evening and during bedtime. Sometimes up to 39.8 degree C. However, his hands and feet are cold when his fever is high. No other symptoms. His throat is a bit red but lung is clear, no ear infections, etc... What s the cause and should I be more worried about his condition? Any advice? Thanks doctors.