Alopecia is common and may include hair loss from all parts of the body. Partial alopecia is thinning of the hair and/or patchy hair loss. Alopecia can negatively impact individual perceptions of appearance, body image, sexuality and self-esteem.
Chemotherapy attacks rapidly dividing cells, including hair matrix cells. 80 to 90% of hair follicles are in the active growth phase (anagen) at any given time making them particularly susceptible to this side effect. The hair follicle resumes its usual division within six to eight weeks after treatment has finished, with hair re-growth taking approximately three to five months.
- Chemotherapy-induced alopecia most commonly affects the scalp hair, beard, and eyebrows; however, axillary, pubic hair, and eyelashes may also be affected. The incidence and degree of hair loss depends on the drug dose, route and schedule. Some agents cause full hair loss, while others may cause thinning or patchy hair loss.
- Radiation-induced alopecia, in the majority of cases, will only cause hair loss in the area of the body that is being treated. However, in some cases alopecia can occur where the radiation beam exits the body, e.g. hair loss on the back of the head may occur for patients receiving radiation to their nasopharynx.
Chemotherapy-induced alopecia usually occurs one to three weeks after treatment begins. Hair regrowth takes approximately three to five months, with some patients experiencing changes to the colour and texture of their regrown hair. The majority of chemotherapy-induced alopecia is reversible once therapy is discontinued. There are however reported cases of permanent alopecia following the use of epidermal growth factor receptor (EGFR) inhibitors, high dose chemotherapy, and bone and marrow transplant. Radiation-induced alopecia usually occurs within two to three weeks of the first treatment dose. Hair loss may continue once treatment has finished, and in some cases alopecia may be permanent or hair regrowth may be patchy.
The incidence and degree of alopecia varies depending upon the specific chemotherapy agent or combination regimen administered, the drug dose and the treatment schedule. High-dose, intermittent, intravenous chemotherapy regimens are associated with higher incidence of total alopecia. While low-dose, weekly, oral chemotherapy regimens are less likely to cause total alopecia. Combination chemotherapy regimens are more likely to cause total alopecia than single chemotherapy agents.
The incidence and degree of radiation-induced alopecia depends on the size of the treatment field, the type of radiation being used, the frequency of treatment, and the total dose.