Chromhidrosis: The Obscure Reason Your Body Can Turn Your Toilet Seat Blue
Health ConditionsSkin Conditions

Chromhidrosis: The Obscure Reason Your Body Can Turn Your Toilet Seat Blue

Chromhidrosis: The Obscure Reason Your Body Can Turn Your Toilet Seat Blue
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Updated on August 6, 2025
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Sweating is an important bodily function that keeps you cool during hot weather and tough workouts. The end result is usually nothing more than sticky skin and the occasional pit-stained T-shirt. But for a small percentage of people, sweating can also leave behind a blue toilet seat.

The phenomenon might be thanks to chromhidrosis, a rare skin condition marked by the production of colored sweat, in shades of blue, green, yellow, brown, or black.

Because chromhidrosis is rare, there's very little data on the condition, making it difficult to pinpoint how many people are affected and whether there's a link between chromhidrosis and factors like race, sex, occupation, geographic location, or the weather.

Types of Chromhidrosis

There are three types of chromhidrosis: apocrine, eccrine, and pseudochromhidrosis.

 Each shows up a bit differently and has its own underlying causes, says Daniel Friedmann, MD, a dermatologist at Westlake Dermatology in Austin, Texas.

1. Apocrine Chromhidrosis

Apocrine chromhidrosis affects the areas of the body that contain apocrine sweat glands. These glands are in the underarm and genital regions, as well as the scalp, torso, eyelids, ears, and nipple areas.

 Apocrine glands secrete a milky, odorless substance when you're stressed, and when that substance combines with bacteria on your skin, it causes body odor.

"All apocrine fluid contains yellow-brown granules called lipofuscin," Dr. Friedmann says. "For people with apocrine chromhidrosis, these secretions contain a greater concentration of highly oxidized lipofuscin granules, giving them a significantly darker green-brown to blue-black color."

Because apocrine glands don't start functioning until puberty (when hormonal stimulation begins),

 this form of chromhidrosis is typically more prominent when a person is younger, with symptoms becoming less severe as they age and apocrine secretion tapers off.

2. Eccrine Chromhidrosis

Eccrine glands are found almost everywhere on the body, except the ear canals, lips, and certain areas of the genital region. They're especially concentrated on the forehead and cheeks, armpits, palms, and soles of the feet.

 These sweat glands are responsible for controlling body temperature, keeping skin hydrated, and protecting the skin barrier.

Eccrine chromhidrosis may be caused by something internal like an infection or excess bilirubin (an orange-yellow pigment formed in the liver) or by something external like the ingestion of certain substances, Friedmann says. Those substances might include water-soluble dyes, heavy metals (like copper), excess food coloring or flavoring, and certain medications (rifampin, an antibiotic; quinine, an antimalarial; and levodopa, a dopamine precursor used to manage Parkinson's).

It's thought that the excess pigments from these internal and external sources make their way to the eccrine glands, where they're excreted along with perspiration, ultimately blending together to create colored sweat.

"Because of its wide range of underlying causes, eccrine chromhidrosis can happen at any age," Friedmann says.

3. Pseudochromhidrosis

Pseudochromhidrosis can also happen at any age and stem from a variety of causes — all of which are external in nature.

 This form of colored sweat is seen when normal perspiration at the skin surface interacts with other compounds, such as dyes (from a new pair of jeans, perhaps), chemicals (such as sunless tanning sprays), or chromogenic bacteria on the skin (bacteria that produce pigments), Friedmann says.

In other words, it's not your sweat that's colored — the color comes from the way your sweat interacts with factors outside your body.

Treatment for Chromhidrosis

Apocrine chromhidrosis is a chronic skin condition; symptoms can regress as you age, but there's no guarantee that they will. Treatment focuses on reducing symptoms as much as possible, but there's no cure.

Apocrine secretion can be triggered by emotions (stress and anxiety), rubbing in apocrine-heavy areas (friction from clothes), and hot showers and baths.

 Doing what you can to reduce these triggers — wearing breathable clothing, taking lukewarm showers, and finding ways to manage stress, such as practicing mindfulness — can be a solid first step.

The primary treatments for apocrine chromhidrosis are topical agents: antiperspirant (such as Drysol) to temporarily plug pores and capsaicin cream to deplete the nerve cells of substance P, an important chemical that controls apocrine gland secretion, Friedmann says.

If topical products irritate your skin, another option is botulinum toxin type A (Botox) injections, which block the nerves that stimulate the sweat glands.

 A few pills can decrease sweat production.

Manual expression of the apocrine glands (squeezing the glands to empty them, similar to popping a zit) can also offer relief, but the results only last up to a few days. Ditto for manual pressure to improve the look of the affected area, with results lasting only 24 to 72 hours.

Treatment for the other two types of chromhidrosis are more promising, though. "Eccrine and pseudochromhidrosis may completely resolve once the cause is avoided or treated," Friedmann says. "Finding and stopping the specific cause is paramount."

This process might involve your doctor testing skin scrapings, secretion smears, or extraction samples from clothing. Once the cause has been confirmed, they can help you determine the best course of action: avoiding the trigger, treating it (with antibiotics, for example), or replacing the trigger with another option (say, a different medication) that doesn't cause colored sweat.

Is Chromhidrosis Something You Need to Worry About?

Chromhidrosis is a harmless skin condition, but because colored sweat can be a symptom of something more serious, it's important to check with your doctor or dermatologist for a diagnosis.

"Your doctor can run the necessary tests to rule out more serious causes of colored sweat, such as infection, jaundice, hematidrosis (bloody sweat), and poisoning," says Hadley King, MD, a New York City–based dermatologist.

Tracking your daily activities for two to three weeks — such as what you eat and any chemicals you come into contact with, as well as vitamins, supplements, or new medications you take — leading up to your doctor's appointment can be helpful in determining your triggers and what the potential culprits might be.

It's also important to talk to your doctor about any emotional distress you're experiencing in relation to your chromhidrosis, as feeling self-conscious about the condition is totally normal, Dr. King says. "Although it's a rare condition, you're not alone. Therapists and counseling are available to help you out," she says.

The Takeaway

  • The blue toilet seat phenomenon may be associated with chromhidrosis, a rare but harmless condition that causes colored sweat, which can stain surfaces.
  • Chromhidrosis isn’t curable, but treatments like topical agents, Botox injections, and addressing triggers may help manage symptoms.
  • See your doctor if you’re having colored sweat. They can help you pinpoint the cause and prescribe treatment if needed.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Chromhidrosis (Colored Sweat). International Hyperhidrosis Foundation.
  2. Wilkes D et al. Chromhidrosis. StatPearls. July 3, 2023.
  3. Sweating and body odor. Mayo Clinic. May 3, 2025.
  4. Hodge BD et al. Anatomy, Skin Sweat Glands. StatPearls. October 10, 2022.
  5. Sweating. International Academy of Cosmetic Dermatology.
  6. Hyperhidrosis. Mayo Clinic. October 25, 2024.
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Susan Bard, MD

Medical Reviewer
Castle Connolly Top Doctor

Susan Bard, MD, is a clinical instructor in the department of dermatology at Weill Cornell Medicine and an adjunct clinical instructor in the department of dermatology at Mount Sinai in New York City. Her professional interests include Mohs micrographic surgery, cosmetic and laser procedures, and immunodermatology.

She is a procedural dermatologist with the American Board of Dermatology and a fellow of the American College of Mohs Surgery.

Dr. Bard has written numerous book chapters and articles for many prominent peer-reviewed journals, and authored the textbook The Laser Treatment of Vascular Lesions.

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Krissy Brady is so out of shape, the health tracker on her phone pings her periodically to see if she’s still alive—so naturally, she became a health and wellness writer. You can find her at Club Meh and on Twitter, where she writes and tweets for the barely functional.

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