Cortisone shots, formally known as corticosteroid injections, are a common medical treatment used to deliver powerful anti-inflammatory medication directly into a targeted area of the body. These injections help manage pain and reduce swelling associated with conditions ranging from joint injuries and arthritis to autoimmune disorders like alopecia areata. While generally considered safe and effective for localized relief, patients often express concern about potential side effects, including hair loss. The risk of hair thinning or shedding depends on several factors, including the injection site, the dosage administered, and the individual’s overall health.
Localized Hair Loss at the Injection Site
The most common form of hair loss directly linked to a cortisone shot is a temporary, localized effect occurring precisely where the medication was administered. This reaction is primarily observed when the injection is given into or near the scalp. However, it can also affect hair growth near joints if the drug diffuses widely, due to the direct, high concentration of the corticosteroid.
This concentrated exposure can lead to dermal atrophy, where the skin and underlying fat tissue thin out. Dermal atrophy temporarily suppresses the activity of nearby hair follicles, causing hair in that small area to fall out. This results in a patch of hair loss directly over or very close to the injection site, sometimes accompanied by a slight depression in the skin.
This localized effect is self-limiting and does not represent permanent hair loss. The hair follicles are suppressed rather than destroyed, meaning they usually recover their function once the high concentration of the medication dissipates. Because the effect is confined to the immediate area of the injection, it is distinct from generalized thinning that can occur with systemic exposure.
How Corticosteroids Affect the Hair Cycle
Corticosteroids can interfere with the natural cycle of hair growth, causing a disruption that leads to noticeable shedding. The hair cycle consists of three main phases: anagen (growth), catagen (transition), and telogen (resting and shedding). The drug’s influence can prematurely force a significant number of hair follicles out of the active anagen phase and into the resting telogen phase.
This sudden, premature shift of hair follicles into the resting stage results in telogen effluvium, characterized by increased, widespread hair shedding. In a healthy cycle, only about 10% of hairs are in the telogen phase, but a systemic disruption can increase this percentage substantially. The shedding often becomes noticeable weeks or months after the initial exposure to the medication.
The biological mechanism involves corticosteroids mimicking the body’s natural stress hormones, which suppresses the metabolic activity of the hair follicle matrix. By altering the signaling pathways that regulate growth, the medication essentially puts the hair production process on hold. This interruption of the anagen phase is the underlying cause for both localized and widespread shedding.
Systemic Cortisone Use and Widespread Thinning
While localized hair loss is a direct result of the injection technique, widespread thinning is associated with the systemic absorption of the drug into the bloodstream. This form of hair loss is more likely to occur with frequent, high-dose injections or oral corticosteroid medications. When the medication circulates throughout the body, it affects hair follicles across the entire scalp, not just at one specific point.
The systemic presence of the corticosteroid influences the body’s hormonal balance and stress response, triggering generalized telogen effluvium. This widespread thinning is a diffuse loss pattern, meaning the hair appears less dense across the entire scalp rather than in distinct patches. Individuals may notice an overall reduction in hair volume or excessive hair falling out during washing or brushing.
The risk of experiencing this systemic side effect depends heavily on factors like the cumulative dose and the duration of treatment. Patients who require repeated or prolonged courses of corticosteroids have a greater chance of experiencing this form of drug-induced shedding.
Recovery and Management of Hair Loss
The hair loss associated with cortisone shots is temporary, and recovery is expected. Since the shedding is caused by a temporary disruption of the hair cycle, the follicles remain viable and are capable of resuming normal growth once the medication concentration subsides. Regrowth generally begins within three to six months after the initial shedding phase starts.
Patience is often the primary management strategy, as the hair cycle naturally takes time to reset and return to the active growth phase. Maintaining good overall health, including adequate nutrition, supports the body’s recovery process and the follicle’s return to the anagen phase. Patients prescribed cortisone should not stop the medication suddenly if they notice hair loss.
Instead of abruptly discontinuing treatment, individuals experiencing noticeable shedding should schedule a discussion with their prescribing physician or dermatologist. A medical professional can assess the pattern of hair loss, confirm the cortisone shot is the likely cause, and determine if an adjustment to the dose or a switch to an alternative treatment is appropriate. Persistent or severe hair loss, or hair loss accompanied by other systemic symptoms, warrants prompt medical consultation to rule out other underlying health issues.