Does Hair Always Grow Back Fully After Chemotherapy?

Some types of chemotherapy medications can cause hair loss.  In most cases the hair grows back. In some situations, however, the hair does not regain full density even months after completion of chemotherapy. What are some reasons that hair does not grow back fully after chemotherapy?  A full assessment is needed to determine all the reasons but a few of the most common reasons are listed here.

Permanent chemotherapy induced alopecia (PCIA). Some chemotherapy drugs can cause permanent damage to the follicular stem cells of the hair follicle and lead to hair loss.  Three common examples include taxanes (used to treat breast cancer), cisplatin (used to treat lung cancer as well as other cancers), busulfan (used to treat blood cancers). There are other drugs that do this as well.

Androgenetic alopecia. Androgenetic alopecia is common in the population. 30-40 % of women and 50-60 % of men have androgenetic alopecia.  Sometimes with hair loss from chemotherapy, androgenetic alopecia can become noticeable a few years sooner.

Drug induced hair loss. Some drugs used in patients after chemotherapy can rarely lead to hair loss.  For example, anastrozole is an example of a drug that can occasionally be associated with hair loss. There are several other examples too.  It is important to know that some drugs will cause hair loss in certain people but not cause hair loss in other people. 

Telogen effluvium (hair shedding). Hair shedding can happen for a variety of reasons, including surgery, infections, thyroid abnormalities, nutritional problems and drugs.  For a variety of reasons, cancer patients may be more prone to telogen effluvium. 

Other hair diseases.   There are about 100 reasons for anyone in the population to lose hair.  Patients who received chemotherapy can develop many other hair loss conditions. It is important to have a thorough evaluation to determine the reasons for hair loss.