My son is 11 years old and anytime his nose start bleeding even in a low temperature?

Nose bleeds are : Common in middle childhood & often reflect irritants like dust, pollen, fumes, smoke etc that the kid is exposed to on a regular basis.These things accumulate in the nasal passages & lead to nasal rubbing when the kids are half asleep or during the day.The trauma causes small capillaries in the nose to blead.Nasal saline wash can remove the irritants & nasal saline gel helps if applied at night.

The most common...: ....Reason for nose bleeds is nose picking. This is exacerbated by irritants like dust, allergens, and dry air that cause the injured lining of the nose to crack and bleed repeatedly. Apply a lubricant like saline gel or petroleum jelly to keep the lining moist and control cracking, and encourage your kid to keep his fingers out of his nose.