Suspected alopecia areta. Bad impacts?

Good morning sir, i was recently shocked to see a patch of hair missing at the back of my hairline. All i remember is that some 3_4 months bk, i was suffering from severe hairloss and i remember of having severe itching in that area. But hardly i knew about this patch of hairloss.I hv been into medication for hairloss since last 2 months. My hairloss issue keeps recurring every now and then eversince i hv hypothyroidism. But this patchy hairloss was a true nightmare. Now my doctor, whom i trust , has asked me to use minokemN 5% along with the medication ,i hv been into . My question is can i use onion juice before every hairwash along with what has been suggested by my dermatologist?? Or it might hv sm bad impacts??please suggest. Regards.