Hello, Thanks for your query. I would come up with these possibilities for this blood with cough , these includes. 1 As there is a long history of smoking , so may be due to cancer of lungs.Diagnosis can be confirmed by X ray chest and M R I of lungs. 2 Tuberculosis , diagnosis can be confirmed by X ray chest and sputum ( mucus ) examination with blood examination. 3 Gingivitis or pyorrhea , diagnosis can be confirmed by physical examination by an E N T specialist . 4 Bleeding disorder is one of the most prominent cause , but in your case this is a least possible reason . Visit the dentist first for check up and your problem continue then go for complete haemogram .and them consult physician. I do hope that you have found something helpful and I will be glad to answer any further query. Take care