Are itchy scalp and excessive shedding after using Propecia a bad sign?

You may be experiencing an allergic reaction. I suggest a consultation with a cosmetic dermatologist with experience in hair restoration and maintenance. Some great options for hair restoration and maintenance are prp injections which can stimulate hair growth. Hope this helps.

You may be allergic. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. 
See an expert. Best, Dr. Emer

Thank you for your question! This is likely how your body is reacting to the treatment. It is neither good nor bad. I would speak to your provider who can look at your scalp to make sure this is not a problem. Best of luck! 

At day22, this is neither a good nor bad sign. It carries no prognostic significance at such and early point. See a physician if concerns persist.

This is likely how your body is reacting to the treatment. It is neither good nor bad. I would speak to your provider who can look at your scalp to make sure this is not a problem. 

The itching may reflect an allergy to this drug. If you stopped it, will the itching go away?  Did you try to take benedryl to manage the itch?

If you feel there is some unusual itching and shedding after starting to use propecia, it is best to follow up with your doctor or hair loss specialist to find the cause.