Hello,
In the absence of a detailed history, I am able to list only a few differentials. The causes of hair fall could be due to stress, fungal infections, alopecia aereata, hormonal imbalance(overproduction of dihydrotestosterone and thyroid hormones irregularities),malnutrition, telogen effluvium and sebum plugs on skin.
I would suggest you to consult a dermatologist and get these possibilities evaluated. Hope it helps. Take care and please do keep me posted on how you are doing or if you have any additional queries. Warm regards.