Hi and welcome to Healthcaremagic. I understand your concerns.
Allergy is on eof the possible causes of nose bleeds. Other inlcude: Allergies, infections, or dryness that cause itching and lead to picking of the nose.
Vigorous nose blowing that ruptures superficial blood vessels.
Clotting disorders that run in families or are due to medications.
Drugs (such as anticoagulants or anti-inflammatories).
Fractures of the nose or the base of the skull. Head injuries that cause
nosebleeds should be regarded seriously.
Hereditary hemorrhagic telangiectasia.
If frequent nosebleeds are a problem, it is important to consult an otolaryngologist. An ear, nose, and throat specialist will carefully examine the nose using an endoscope, a tube with a light for seeing inside the nose, prior to making a treatment recommendation.
I hope I have answered you query.
Kindly regards. Wish you a good health.