Hair thinning may be related to the stress of the previous illness, hormonal problems, pregnancy, certain medications
, infections, or may be a part of an underlying disease such as lupus or diabetes
. Medicines that can cause hair loss include blood thinners, medicines used for gout, chemotherapy, too much vitamin A, birth control pills and antidepressants. Fungal infections of the scalp can also cause hair loss but can be easily treated with antifungal medicines.