Topical steroids, also known as topical corticosteroids, are common medications prescribed to reduce inflammation and suppress immune responses in the skin. These anti-inflammatory agents are routinely used for managing various dermatological conditions, such as eczema, psoriasis, and dermatitis. While highly effective for calming inflamed skin, their use is associated with a range of localized side effects. One particular concern is the potential for unwanted hair changes, specifically increased hair growth, a condition known as hypertrichosis.
The Phenomenon of Steroid-Induced Hair Growth
Topical steroids can cause the growth of fine, unwanted hair, known as hypertrichosis, in the specific area of application. This strictly localized side effect involves the development of vellus hair that is often longer, darker, and denser than the surrounding hair. Hypertrichosis is a recognized, though less frequent, adverse effect associated with prolonged or intensive use of these medications.
It is important to distinguish hypertrichosis from hirsutism, which is excessive hair growth in women following a male pattern caused by hormonal imbalance. Steroid-induced hypertrichosis is not related to androgens and is confined only to the treated skin area.
Hypertrichosis is often a cosmetic concern, sometimes prompting patients to discontinue treatment prematurely. Using topical corticosteroids exactly as directed minimizes the risk of such visible side effects. While generally reversible, the effect often requires a change in the treatment regimen.
Biological Mechanisms Driving Follicle Changes
The active compounds in topical steroids are glucocorticoids, which bind to specific receptors located within skin structures, including the hair follicle. Hair growth occurs in a continuous cycle involving three main phases: anagen (growth), catagen (transition), and telogen (resting).
Steroids promote hair growth by interfering with this cycle, specifically by modulating the anagen phase. Glucocorticoids prolong the anagen phase, extending the time the hair follicle actively produces a shaft. This extended growth period results in hair that is longer and potentially thicker.
Lengthening the active growth phase increases the overall density of hair in the treated area, as more follicles are actively producing hair. This localized effect is a direct result of the medication’s high concentration at the site of application.
Factors Influencing Hair Changes
The likelihood of experiencing steroid-induced hair changes is not uniform and depends heavily on several factors related to the medication and the application site. The potency of the topical steroid is a primary determinant; higher-potency formulations are significantly more likely to cause side effects, including hypertrichosis, than their milder counterparts. Furthermore, the duration of use is a major risk factor, with long-term, continuous application significantly raising the risk profile.
The location on the body where the steroid is applied also influences the outcome due to differences in skin thickness and absorption rates. Hypertrichosis is particularly common on the face and forehead, where the skin is thin and the absorption of the medication is higher.
Conversely, prolonged use in areas of thin skin or when the application is covered with an occlusive dressing can cause a separate effect: skin atrophy, or thinning. Skin atrophy can paradoxically lead to hair thinning or loss because the degradation of the dermal structures fails to support the hair follicle properly. The specific formulation, such as an ointment versus a cream, may also play a minor role due to differences in skin penetration.
Treating and Reversing Unwanted Hair Effects
Management of steroid-induced hypertrichosis focuses on addressing the root cause: the medication itself. The most effective step is the discontinuation or gradual tapering of the topical steroid, which must be done under physician supervision. Abrupt cessation is avoided to prevent a rebound flare of the original skin condition.
Once the steroid is removed, the hair follicle cycle can begin to normalize, and the hypertrichosis is often reversible. This process is not immediate and may take several months to resolve completely, corresponding to the length of the hair growth cycle.
For immediate cosmetic relief during the reversal period, temporary hair removal methods such as shaving, trimming, or waxing can be utilized. A dermatologist may also suggest topical treatments designed to slow hair growth, such as eflornithine hydrochloride cream, particularly for facial hypertrichosis. Consulting a medical professional is necessary to determine the safest course of action.