Yes, absolutely. Five-year-olds do not have the capacity to observe themselves, so to speak, so they often do not call attention to varius medical symptoms. If a child is ill by way of troublesome allergies, their mood can certainly be influenced. In normal children, the most frequent sources of irritability are illness, tiredness, and hunger.
I'm not sure about the allergy symptoms being the cause (I'm uninformed in that area), however I do know that respiratory allergies can cause sleep problems and poor oxygen saturation for children. Sleep deprivation in children can translate into emotional lability, poor impulse control, higher activity levels, etc. Since he's being treated for allergies, the doctors in that field should be aware of the association. If that seems like your son, I'd suggest asking the doctor for his opinion at the next appointment.
Yes, absolutely. Five-year-olds do not have the capacity to observe themselves, so to speak, so they often do not call attention to varius medical symptoms. If a child is ill by way of troublesome allergies, their mood can certainly be influenced. In normal children, the most frequent sources of irritability are illness, tiredness, and hunger.