Brief Answer:
Will need some more information to understand the most possible diagnoses

Detailed Answer:
Hello,

Thank you for using HCM,

I understand your concern.

-If I was your caring doctor I would check the skin of your head and see if it has any scales, or if its greasy or if has dandruff. Most of the cases the odor comes from problems in the skin, which needs to be treated accordingly.
- Other things to consider is the shampoo you are using. Have you changed it recently? Maybe it makes your skin there more greasy, and it causes bad odor.
- What other things have changed recently? Sometimes people have their characteristic odor, that for other people it may smell not good, and for some good. Have you noticed if this is a new problem, or you have had it before. If you have had it, then it most probably is the usual odor of your skin.
- Any medication you have started recently?
- Is your hair long? Sometimes shortening it may help.

Please ask your girlfriend to check the skin of your head, and kindly give me the information asked above, and I will give a more thorough opinion on the diagnoses I think it is more probable.

Looking forward to your follow-up question.

Take care,

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Brief Answer:
Seborrhoic dermatitis or fungal infection.

Detailed Answer:
Hello XXXXXXX

Thank you for asking a follow-up question.

What you are describing seems like a seborrhoic dermatitis or a fungal infection.

In both cases I would recommend to either use a antifungal solution for the head hair and the beard one, or a shampoo. They have specific uses, depending on the type, written in the box. Some options are ketoconazole 2% or clotrimazole 1%.
If in your country you will need to have a prescription for it, then you will need to consider a visit to the dermatologist.

Let me know if you have other questions or concerns.

Take care.

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