Hair Loss — Possible Medical Causes

Hair loss is a common concern affecting people of all ages and genders, with loss of scalp hair causing psychological distress and affecting quality of life adversely. While many assume hair loss is simply genetic or age-related, numerous medical conditions and nutritional deficiencies can contribute to this frustrating problem. Understanding the potential underlying causes may help identify treatable conditions that are affecting hair health. Hair follicles are rapidly proliferating organs with much requirement of blood supply, and the relationship between micronutrients and hair loss has been evaluated in several studies since the 1960s. From thyroid dysfunction to iron deficiency, various medical factors can disrupt the normal hair growth cycle, leading to increased shedding, thinning, or even noticeable bald patches.

Strong evidence links thyroid hormones to hair loss, with both overactive and underactive thyroid conditions potentially causing hair thinning. When someone has an underactive thyroid (hypothyroidism), they may experience hair loss (alopecia), along with prolonged shedding (telogen effluvium), as well as dry, brittle, and lackluster hair. Iron deficiency is another significant factor, as when you don't have enough iron, your body can't produce the hemoglobin in your blood. Hemoglobin carries oxygen for the growth and repair of cells in your body, including the cells that stimulate hair growth. Hormonal imbalances, particularly involving testosterone and its derivative DHT (dihydrotestosterone), can also contribute to hair loss patterns. Most studies show an inverse relationship between serum vitamin D levels and non-scarring alopecias such as telogen effluvium, androgenetic alopecia, alopecia areata, and trichotillomania. Additionally, one chief sign of zinc deficiency is hair loss, as this essential mineral plays crucial roles in cell reproduction and protein synthesis necessary for healthy hair growth.

Consider laboratory testing if experiencing sudden or significant hair loss that goes beyond normal daily shedding of 50-100 hairs. Testing may be particularly valuable when hair loss is accompanied by other symptoms such as fatigue, unexplained weight changes, feeling cold, or changes in energy levels. It is practice at the Cleveland Clinic Foundation to screen male and female patients with both cicatricial and noncicatricial hair loss for iron deficiency. Although this practice is not evidence based per se, treatment for hair loss is enhanced when iron deficiency, with or without anemia, is treated. Women experiencing hair loss during periods of hormonal change, such as menopause or after pregnancy, may benefit from comprehensive hormone and nutrient testing. Testing is also recommended for those with rapid onset hair loss, as this pattern often suggests an underlying medical condition rather than typical genetic hair loss.

Test results can help identify treatable underlying causes of hair loss. The hair loss is typically reversed after your thyroid hormone levels are normalized, but this may take some time. For thyroid function, abnormal TSH levels may indicate hypothyroidism or hyperthyroidism, both of which can cause hair thinning. Iron studies showing low ferritin or iron deficiency suggest a potentially reversible cause of hair loss, as most hair loss related to iron deficiency is not permanent. Testosterone levels, when elevated alongside genetic sensitivity, may contribute to pattern baldness through DHT conversion. However, men with male pattern baldness may actually have lower circulating levels of testosterone but higher levels of the enzyme that converts testosterone to DHT, or you may simply have genes that give you hair follicles that are highly sensitive to testosterone or DHT. Vitamin D deficiency may indicate a contributing factor to hair loss, particularly in cases of diffuse thinning. It's important to remember that normal test results don't rule out hair loss from other causes, including genetics, stress, or other medical conditions not covered by these tests.

Maintaining optimal nutrition supports healthy hair growth and may help prevent deficiency-related hair loss. Eat a healthy, balanced diet with iron-rich foods like spinach, peas, lean proteins — like pork and salmon — and dried fruit. Add foods high in vitamin C to your diet as these foods allow your body to absorb iron in a more efficient manner. Managing stress levels is important, as chronic stress can disrupt hormone balance and trigger temporary hair loss conditions like telogen effluvium. The best tactic is to be gentle with your hair. If you're dealing with hair loss for any reason, it's important to be aware of the sensitivity of your hair follicles. Avoid tight hairstyles, excessive heat styling, and harsh chemical treatments that can damage already fragile hair. Getting adequate sun exposure or considering vitamin D supplementation may help maintain optimal vitamin D levels for hair health.