### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
My four year old son recently had a pretty bad bloody nose in the middle of the night. He has has these before in the winter, so we didn t think too much of it. (There is a humidifier in his bedroom that runs all night every night, and we put Vaseline in his nostrils at bedtime.) Just a few days later, he had a meltdown from being overly tired, and his nose started to bleed again. Just a little this time; it stopped fairly quickly. After this episode, he developed a hacky, dry cough, and he s had another incident of his nose bleeding slightly when he started to cry. He doesn t have a fever, but this dry cough has persisted for two and a half days now, and he s never had nose bleeds this frequently before. We have just today added a larger humidifier in our living area of the house to see if that will help. He takes a high-quality multi vitamin every morning, and we are adding a children s C supplement now. Any ideas what this could be? (It hasn t been a particularly cold or dry winter here.)

### output:

Hello and welcome to Ask A Doctor Service.  I reviewed your query and here is my answer. In such a patient, there needs some tests to find out what's causing him nasal bleeding. Cough can be explained by nosebleed. Does he bleed from any other place or is there any rash or petechial on his body? Is there any bleeding disorder in your family? How about his platelet counts? If there is no to all these questions, does he had of habit of pricking his nose or putting his fingers in nose frequently? As this has increased in frequency, so you need to consult your doctor.  Till that, keep applying Vaseline to his nose at least twice a day, keep him away from heat and Chat Doctor.  If there is a bleed, then apply pressure on nose, keep his head tilted forward and if available put ice packs or pour water over his head. Hope I answered your question.  Feel free to ask if you have any doubt before contacting your primary doctor. Thanks.