Hyperparathyroidism (HPT) is caused by overactive parathyroid glands releasing excessive parathyroid hormone (PTH), leading to abnormally high levels of calcium in the blood (hypercalcemia). While HPT is not a primary cause of common hair loss conditions like pattern baldness, the resulting hormonal and mineral imbalances can disrupt the normal hair growth cycle. This article explores the connection between an overactive parathyroid gland and hair follicle health, and what can be expected following treatment.
Understanding Parathyroid Hormone and Calcium Regulation
The parathyroid glands are four small glands located in the neck, near the thyroid gland. Their function is to produce Parathyroid Hormone (PTH), the body’s primary regulator of calcium. PTH ensures that calcium levels in the bloodstream remain within a healthy range, necessary for nerve function, muscle contraction, and bone strength.
When blood calcium levels drop, PTH signals the bones to release stored calcium. It also encourages the kidneys to retain calcium and prompts the intestines to absorb more calcium from food by activating Vitamin D. HPT occurs when one or more glands become overactive, producing PTH regardless of the body’s needs. This excess PTH continuously pulls calcium from the bones and prevents its proper excretion, leading to chronic hypercalcemia.
The resulting high calcium and high PTH environment is a systemic imbalance affecting multiple organs, including the kidneys and bones. This endocrine disruption creates the physiological backdrop against which hair changes and potential hair follicle distress can occur.
Direct Links Between Hyperparathyroidism and Hair Follicle Health
The hair follicle is an active biological structure that depends on precise signaling and nutrient balance to cycle through its growth phases. The elevated levels of calcium and PTH characteristic of HPT can interfere with this process, leading to hair thinning or loss. PTH and a related protein, PTHrP (parathyroid hormone-related peptide), directly influence the hair follicle cycle.
These hormones interact with receptors on hair follicle cells. Dysregulation can prematurely push the follicles from the active growth phase (anagen) into the resting and shedding phases (catagen and telogen). This shift often results in telogen effluvium, characterized by diffuse hair shedding across the scalp. The hair loss is typically generalized thinning, rather than patchy bald spots.
Excessive calcium in the bloodstream can also affect microcirculation in the scalp. High concentrations of calcium may lead to deposits or stiffening in the small blood vessels supplying the hair follicles. This restricts the blood flow and nutrient delivery required for healthy hair growth. This chronic deprivation weakens the follicles over time, manifesting as noticeable thinning, especially in cases of long-standing HPT.
Resolution of Hair Loss Following HPT Treatment
Hair loss caused by HPT is often reversible once the underlying endocrine issue is resolved. Treatment for primary HPT, typically parathyroidectomy (surgical removal of the overactive gland), restores the body’s normal calcium and PTH balance. Removing the disruptive signal allows the hair follicles to gradually return to their normal growth cycle.
Hair regrowth is a slow process that follows the natural hair cycle, so improvements are not immediate. Patients usually notice a reduction in shedding and the start of thickening within six months to a year after successful surgery. The timeline for recovery is consistent with the natural pace of the hair growth cycle.
It is important to consult a dermatologist alongside the endocrinologist to rule out other potential causes of hair loss. While HPT treatment addresses the mineral imbalance, a dermatologist can help manage the hair regrowth process and confirm there are no co-existing conditions contributing to the thinning. The prognosis for hair recovery is generally positive.