Causes of hair loss

Sex steroid hormones drive the development of androgenetic alopecia (also known as male pattern hair loss). These hormonal effects are largely influenced by genetics. However, there are many other reasons why your hair may be falling out.

Causes of hair loss include:

1. Abnormal levels of non-sex steroid hormones
2. Problems with diet and/or nutrition
3. Certain medical conditions or medications
4. Stress and other lifestyle factors.

In this article, we discuss these four factors, as well as the hair loss disorders they might trigger in greater detail. Since these conditions are all treated differently, it’s important to discuss any unusual shedding with a physician.

What hormones cause hair loss?

Dihydrotestosterone (DHT) is recognized as a primary cause of male pattern hair loss. DHT acts on the dermal papilla, the region of the hair follicle that controls the production of androgen (male sex steroid) receptors and the 5-alpha reductase enzyme. This increased hormonal activity triggers follicular miniaturization and eventually, hair loss.

In some men, normal levels of androgens are sufficient to trigger hair loss (Cranwell & Sinclair, 2016). This suggests that factors other than androgens may play a role. In fact, researchers have identified other hormones and hormone-like molecules that can affect the dermal papilla and cause changes in hair growth.

Examples of these molecules include: melatonin and thyroid hormones (Heilmann-Heimbach et al., 2020). Each of these molecules has the potential to bind to dermal papilla cells in the hair follicle and trigger biochemical changes. These changes can go on to impact cell growth and metabolism within the hair follicle and surrounding tissues.

Can diet cause hair loss?

Possibly. We know that vitamins and minerals are important facilitators of the growth of hair follicles, but exactly which ones do and what their optimal levels are, is still a matter of debate (Almohanna et al., 2018).

While most people don’t have dietary deficiencies serious enough to cause extensive loss of hair, there are two micronutrients that are worth paying attention to: Vitamin D and iron. Your diet should include the daily recommended amounts of these micronutrients.

What illnesses and medications cause hair loss?

Certain health conditions, medications and even major surgery can be causes of hair loss. Systemic, chronic and inflammatory illnesses such as lupus, inflammatory bowel disease and psoriasis may cause diffuse shedding (Harrison & Bergfeld, 2009). These health conditions are associated with increases in chemical signalers that can damage healthy tissues over time.

Additionally, many common medications, such as those prescribed to control blood pressure and mood disorders, may trigger hair loss as a side effect.

Drug-induced hair loss is typically noticeable within 12 weeks of starting a medication and continues as long as one remains on therapy (Harrison & Bergeld, 2009). If you suspect that medication may be causing your hair loss, you must consult a physician prior to making any changes.

Aside from inflammatory disorders, fungal or bacterial infections may also cause hair loss. The latter are often accompanied by scalp redness, sores, lesions or swollen glands and should be examined and treated by a physician (Phillips et al., 2017). One example is Tinea capitis, a common fungal infection that results in patchy bald spots that usually resolves with the help of an oral or topical antifungal.

Can stress cause hair loss?

Absolutely. Periods of stress are accompanied by increased secretion of corticotropin-releasing hormone (CRH) in the brain. CRH is a molecule that triggers inflammation, as well as the downstream production of the stress hormone, cortisol.

Inflammation is part of the immune response. It’s counterproductive to hair growth because it encourages hair follicles to move into the catagen (regression) phase of the hair growth cycle.

During the regression phase, the follicle stops producing the hair fibre and shrinks in preparation for the rest phase (Heilmann-Heimbach et al., 2020). Early regression has been linked to the production of shorter, weaker hairs. When this happens en masse, telogen effluvium, or sudden stress-related shedding, may occur.

In addition to this, high levels of stress hormones may interfere with cell signaling pathways and accelerate the breakdown of key structural components of skin, such as proteoglycans and hyaluronan (Thom, 2016). You could start noticing dryer, itchier skin or changes in hair texture as a result.

The takeaway

While androgens such as DHT are associated with premature shedding, it is important not to overlook other causes of hair loss. Based on the discussion above, it’s clear that not all hair loss requires pharmaceutical intervention.

In some cases, lifestyle adjustments can have positive effects on your hair and beyond. This is why it’s important to keep your physician up to date about any changes to your health, including increased shedding. This proactive approach can help ensure that any issues are promptly identified and treated if necessary.