Hair loss is a common concern for individuals undergoing cancer treatment. While chemotherapy and radiation are widely known to cause hair shedding, many don’t realize that cancer itself can also contribute to hair loss. This article explores instances where the disease, rather than its treatment, leads to changes in hair health.
Clarifying Hair Loss in Cancer
Hair loss in cancer patients typically stems from two main origins: as a side effect of cancer treatments or as a direct consequence of the cancer itself. The most common cause is cancer therapies, which target rapidly dividing cells. Chemotherapy drugs, for instance, destroy fast-growing cancer cells but also affect other quickly proliferating cells, including those in hair follicles. This widespread impact can lead to hair loss across the entire body, including the scalp, eyebrows, and eyelashes.
Radiation therapy causes hair loss specifically in the area being treated. If radiation is directed at the head, hair in that region may fall out, and the extent of loss depends on the dose and area irradiated. Targeted therapies and hormonal therapies can also induce hair thinning or patchy hair loss, though these effects are generally less severe compared to conventional chemotherapy. Beyond these treatment-related effects, cancer itself can also lead to hair loss through distinct mechanisms.
Cancers Directly Leading to Hair Loss
Certain cancers can directly cause hair loss through localized effects or specific biological mechanisms. Skin cancers on the scalp, such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), can directly affect hair follicles, leading to hair loss. These cancerous cells invade and destroy normal follicular structures, with the severity of hair loss varying based on the tumor’s size and location. Basal cell carcinoma on the scalp, for example, might present as an alopecic plaque. Squamous cell carcinoma on the scalp can also manifest as crusted or scaly patches, or non-healing sores, causing hair loss.
Specific types of lymphomas, particularly cutaneous T-cell lymphoma (CTCL), can also directly cause hair loss (alopecia). This occurs when cancerous T-cells infiltrate hair follicles, interrupting growth. Hair loss in CTCL can appear as patchy areas or, in more advanced cases like Sézary syndrome, as a more generalized hair loss. This can be one of the earliest signs of the lymphoma, sometimes appearing years before other skin symptoms.
Paraneoplastic syndromes can also contribute to hair loss. These syndromes arise when a tumor produces substances, like hormones or immune modulators, that affect distant tissues or organs, even if the tumor is not on the scalp. These substances can interfere with the normal hair growth cycle, leading to hair changes or loss.
Systemic Effects of Cancer and Hair Health
Beyond direct invasion or specific paraneoplastic syndromes, the broader impact of cancer on the body can indirectly contribute to hair thinning or loss. Cancer can alter nutritional status, leading to deficiencies that affect hair health. Conditions like cancer cachexia, a wasting syndrome, and general malnutrition can deprive hair follicles of essential vitamins, minerals, and proteins necessary for growth. Hair follicles, being among the fastest-growing cells, are sensitive to such nutrient shortages.
Hormonal imbalances also play a role in cancer-related hair changes. Certain cancers, especially those affecting endocrine glands, or the body’s stress response, can disrupt hormone levels. Hormones like androgens, estrogens, and thyroid hormones regulate the hair growth cycle, and their dysregulation can lead to hair thinning or shedding. For instance, changes in estrogen and progesterone levels can shorten the hair’s active growth phase, leading to increased shedding.
Chronic inflammation and the stress imposed by cancer on the body can trigger a condition called telogen effluvium. This condition causes a sudden, widespread shedding of hair, often a few months after a significant physical or emotional stressor, such as a cancer diagnosis. The inflammatory response associated with cancer can also contribute to this accelerated shedding. The immune system’s response to cancer can sometimes lead to autoimmune hair loss conditions like alopecia areata, where the immune system mistakenly attacks hair follicles.