Brief Answer:
It could be due to inflammation or nose picking

Detailed Answer:
Hello and welcome,

Blood with phlegm in cases of allergy or any long-term cough is not worrisome. Many times in these harmless cases, phlegm will just be tinted with blood. So nothing to worry.
Worrisome symptom would be unexplained loss of weight, chest congestion, clammy hands and feverish feeling, which may point towards conditions like cancer or tuberculosis. Symptoms of these conditions are much more dramatic.
If you donot know the diagnosis for your cough, please see a doctor for further tests.

Hope this helps. Let me know if I can assist you further.
Dr Vaishalee

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