Doctors describe rare case: antibiotic turned patient’s skin black

A 68-year-old woman in the United States began to experience a dramatic darkening of her skin — bluish-black patches resembling massive bruises first appeared on her legs, before the unusual pigmentation spread to her arms and even her tongue.

The symptoms began just two weeks after she had been prescribed a new medication. The unusual case was published in The New England Journal of Medicine.

The woman had been taking the antibiotic Minocycline, a drug commonly prescribed for rosacea, a chronic inflammatory skin condition affecting the face.

Doctors diagnosed the patient with a rare form of drug-induced hyperpigmentation: the skin on her arms and legs gradually developed a bluish-gray and nearly black discoloration.

What particularly surprised physicians was how rapidly the reaction developed — such changes usually occur after months of treatment, not within a couple of weeks.

According to doctors, Minocycline can form dark pigment compounds inside the body that gradually accumulate in the skin. Researchers believe the antibiotic’s breakdown products bind to iron and melanin — the pigment responsible for skin color. As a result, the tissues essentially begin to darken from within.

Doctors immediately discontinued the medication and advised the woman to avoid sunlight, since ultraviolet exposure can worsen pigmentation. However, even after six months, the spots had not completely disappeared — they had only faded slightly. In some cases, such pigmentation may persist for years or even permanently.

The authors of the report emphasized that this side effect is considered relatively rare, but far from unique. According to some estimates, skin discoloration may occur in nearly one-third of rosacea patients who take Minocycline long term. However, physicians described such a rapid onset of symptoms as highly unusual.

This is not the first case in which medications have literally changed the color of the human body. Doctors had previously described a patient whose blood turned dark blue after using a pain-relief gel containing benzocaine. In that case, the woman developed methemoglobinemia, a dangerous disorder that impairs the blood’s ability to carry oxygen.

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