Medication-induced hair color changes, a phenomenon known as chromotrichia, are an uncommon but documented side effect of certain treatments. This discoloration occurs when therapeutic compounds interact with the biology of the hair follicle and shaft, leading to a visible shift in pigment. When the change specifically results in a yellow hue, it is referred to as xanthotrichia. These chemically driven processes often cease or reverse once the causative medication is discontinued.
Medications Known to Induce Yellow Hair Color
The most recognized systemic drug associated with true yellow hair discoloration is the antimalarial agent quinacrine. Quinacrine is sometimes prescribed for autoimmune conditions like lupus erythematosus or for malaria prophylaxis. The yellowing effect is a well-established clinical finding characteristic of this drug. This discoloration is dose-dependent and typically affects the hair of the scalp. It can also be seen on the skin and in the whites of the eyes (sclera).
Certain classes of chemotherapy agents are also implicated in causing various hair color changes, including yellowing or a brassy, yellowish-red tone. Drugs that target rapidly dividing cells can disrupt the hair’s natural pigment production cycle. While many chemotherapeutics can cause hair lightening or darkening, some have been associated with a noticeable yellowing effect.
Other medications can cause yellowing, often via indirect mechanisms or in combination with other colors. The antibiotic minocycline, a tetracycline derivative, is known for causing blue-gray or brown discoloration in the skin, but it can also cause yellow-tinged pigmentation in tissues. In rare instances, topical treatments like selenium sulfide shampoo have been reported to cause temporary yellow discoloration of white or light-colored hair.
How Drugs Alter Hair Pigmentation
Drug-induced yellowing of the hair primarily occurs through drug deposition within the hair shaft. Hair is largely composed of the protein keratin, and the shaft is a non-living structure that grows from the living hair follicle beneath the scalp. When a drug is circulating in the bloodstream, it can be incorporated into the newly forming keratin matrix.
Quinacrine, for example, is a highly lipid-soluble molecule that binds strongly to tissue components, including keratin in the hair cortex. The drug or its metabolic byproducts are physically deposited into the growing hair structure, staining the hair from the inside out. This direct deposition of the yellow compound causes the characteristic yellowing.
A second mechanism involves a drug’s interference with melanin, the natural pigment that determines the hair’s original color. Drugs can alter the production or structure of this pigment, leading to a color shift. Yellowing is often more pronounced in individuals with lighter hair because their hair naturally contains less eumelanin, the dark brown-black pigment, to mask the yellowish hue of the deposited drug. The discoloration results from the drug’s systemic presence affecting the hair as it forms.
Strategies for Addressing Hair Discoloration
The primary step in addressing medication-induced hair discoloration is to consult with the prescribing physician. Patients should never abruptly stop taking a prescribed medication without first discussing the side effect. The physician can assess if the discoloration is drug-related and determine if a dosage adjustment or a switch to an alternative drug is medically appropriate.
The most reliable resolution for drug-related discoloration is the natural process of hair turnover. Since the hair shaft is dead tissue, the discolored portion will not change color once it has grown out. The hair returns to its original color only as new, unexposed hair grows in, pushing the affected hair toward the tips. This process can take several months, as scalp hair typically grows about a half-inch per month.
In the interim, cosmetic solutions can offer temporary relief from the visible yellowing. Specialized shampoos and conditioners containing purple or violet pigment are commonly recommended. Based on color theory, violet is the complementary color to yellow, meaning the purple pigment chemically neutralizes the brassy yellow tones on the hair surface.
These toning products are generally safe, but they only provide a temporary corrective effect on the hair shaft surface. For more resistant or severe cases, a professional hairstylist may use toners or dyes. However, some medication-induced stains are highly resistant to standard coloring processes. Chemical treatments should be approached with caution to avoid further hair damage.