In my opinion, your single episode of a small streak of blood was likely caused by acute bronchitis or a severe respiratory infection. Intense coughing can irritate the delicate lining of your airways, causing a tiny blood vessel to break—much like a minor nosebleed. Since 50 days have passed and you have no current symptoms like cough, fever, or weight loss, it is highly likely that the underlying cause has resolved on its own.
Next Steps
Even though you feel fine now, you should take the following actions:
Consult a General Practitioner: It is best to have a routine check-up to rule out any underlying issues, especially if you are over age 40 or have a history of smoking.
Inform your Doctor of Risk Factors: Mention if you have any history of blood clots, heart disease, or travel to areas where tuberculosis is common.
Health Tips
Monitor for Red Flags: Seek immediate medical care if you experience a return of blood in your phlegm, new chest pain, shortness of breath, or unexplained weight loss.
Avoid Irritants: Stay away from cigarette smoke and environmental pollutants that can irritate your airway lining.
Stay Hydrated: Drinking plenty of fluids helps keep your mucous membranes moist, which reduces the chance of irritation during future minor illnesses.