Hello, thanks for the query to H.C.M.Forum. Sudden fall of temperature causes constriction of air ways in few persons. This is a type of allergy. When there is allergy than there are runny nose, blockage of nostril,red eyes,mild itch in eyes. When infection is added in this condition than there develops mucus( forms) and flowing of mucus starts as in your case. As far as concerned about blood this may be due to congestion in the nose or throat or in lungs. Because nearly from one month blood is there in mucus,so please consult a physician and get an X ray chest and blood ,sputum (mucus) examination. These investigations reveals the complete disorders whether due to allergy or other disease. Hope I have answered your query. If any further question I will be happy to help. Wish you healthy life. Dr. HET