Hi, Thank you for your reply. You have made me think. Our son's room was recently added to the house. It is South facing and therefore cold. There was damp on the walls when we recently purchased the house. There were also carpets which we removed as we thought dust mites might be causing the problem - to no avail. We also use a humidifier in his room at night. It is a cold steam one. Could that have any affect? Possibly we should replace the water each evening even if only a little is left over from the previous evening. Thanks once again.
Hi
Welcome to the forum!
A three year old with a constant runny nose can be having allergic rhinitis. The child is probably allergic to something in his environment. Common allergens are pollen, mold, dust, pet dander, food, cosmetics (like powders, shampoos, soaps), smoke, pollution, dust storms or drugs. Please think this over—a damp wall or an old AC, pets at home, immediate neighborhood or school or some food.
Basically an allergy test will help determine the cause.
Hope this helps. It is difficult to comment beyond this at this stage. Please let me know if there is any thing else and do keep me posted. Take care!