When facing unexpected hair shedding, it is understandable to question all potential causes, including sexually transmitted infections (STIs). While hair loss is not a typical or frequent symptom of most STIs, certain infections transmitted through sexual contact can indeed trigger changes in hair growth. Understanding which specific infections are involved and the processes behind the shedding can help clarify this concerning symptom.
STDs Directly Linked to Hair Loss
The most definitive and direct link between a sexually transmitted infection and hair loss is seen with Syphilis, specifically during its secondary stage. This condition is medically termed alopecia syphilitica and affects approximately 3% to 7% of individuals with secondary syphilis. The hair loss is characteristically non-scarring, meaning the hair follicles are not permanently destroyed, which is a hopeful sign for recovery.
The pattern of hair loss in syphilis is often described as “moth-eaten,” characterized by small, scattered, irregular patches of thinning hair across the scalp, giving it a patchy appearance. Although the scalp is the most common area, the infection can also cause hair thinning in the eyebrows, beard, and other body hair. While Syphilis is the only STI known to directly cause hair loss, Human Immunodeficiency Virus (HIV) is indirectly associated with hair thinning through related complications.
HIV-related hair loss is generally not caused by the virus itself directly attacking the hair follicle. Instead, it is often a side effect of the chronic disease state or a weakened immune system. Patients with advanced HIV or AIDS may experience hair loss due to severe nutritional deficiencies, such as low levels of zinc, copper, or iron, which are vital for hair growth. Certain medications, particularly older antiretroviral drugs or treatments for co-occurring infections, can also list hair loss as a possible side effect. Common STIs such as Chlamydia, Gonorrhea, and Human Papillomavirus (HPV) are not known to cause hair loss directly.
The Mechanisms Behind Hair Shedding
The underlying cause for the hair loss seen in secondary syphilis is a disruption of the normal hair growth cycle, primarily leading to a condition called Telogen Effluvium. Hair follicles naturally cycle through growth (anagen), regression (catagen), and resting (telogen) phases. Systemic stressors, such as a serious infection or high fever, can prematurely push a large number of growing hairs into the resting phase.
The full shedding from this disruption typically appears about three months following the initial stressful event, which aligns with the timing of secondary syphilis symptoms. The systemic inflammation and immune response triggered by the Treponema pallidum bacteria are believed to be responsible for this premature shift in the hair cycle. This inflammatory process can affect the environment surrounding the hair follicle, causing it to slow or halt production.
In cases of the “moth-eaten” pattern, the patchy appearance is thought to be the result of a localized inflammatory response. For individuals with HIV, the mechanism is often related to the overall body burden of chronic illness, which acts as a persistent stressor on the hair cycle. This chronic stress, combined with the compromised ability to absorb nutrients, can deprive hair follicles of the resources needed for healthy growth.
Treatment and Hair Regrowth
Hair loss resulting from secondary syphilis is almost always temporary and reversible once the underlying infection is cured. Since alopecia syphilitica is a non-scarring form of hair loss, the hair follicles retain the ability to regenerate hair. The definitive treatment involves addressing the bacterial infection, typically with an intramuscular injection of the antibiotic penicillin G.
After successful treatment, patients usually begin to see signs of hair regrowth within five weeks to three months. Complete restoration of normal hair density generally occurs within four to twelve months after the antibiotic therapy. Follow-up with a medical professional is important to ensure the infection has been eradicated and to monitor regrowth progress.
For hair loss associated with HIV, the approach involves managing the chronic condition and addressing the indirect causes. This often includes optimizing antiretroviral therapy (ART) to control the viral load and consulting a doctor if a specific medication is suspected of causing the shedding. Nutritional support, including supplements for any identified deficiencies, is also a significant part of the recovery process. Removing the systemic stressor—whether it is the active infection, a medication side effect, or poor nutrition—is the first step toward natural hair recovery.