There are some things we take as simple, comforting truths. When we drop a pencil, it will fall down instead of up. In the evening, the sun will set, and in the morning, it will rise. And when we sweat, it will come out of our pores as a clear liquid. These are things we can depend on, things we can take solace in knowing we can predict.
Which is why one can imagine how disconcerting it must have been for a 26-year-old nurse when she began excreting red sweat in the late 1990s. After five months of concern and fighting stubborn stains, the woman sought medical attention. Physicians harvested sweat from her sebum (the natural oils that waterproof and moisturize our skin and hair) using ether to separate the sweat from the rest of the materials. They compared it to the nurse's stained clothing and found that the woman had a case of chromhidrosis.
Chromhidrosis is an extremely rare condition that causes a person to excrete colored sweat. It can come from either of the two types of sweat glands (more on that on the next page), but the common thread is that the colored sweat is produced in the gland. This differentiates it from another condition, called pseudochromhidrosis, where clear sweat is produced and mixes with a coloring agent when it reaches the skin [source: Musel]. The classic case most often cited is the blue sweat found on copper miners -- the mineral mixes with the sweat on the skin, causing the pigmentation. The case literature on pseudochromhidrosis generally ends with a disappearance of the symptoms when the patient discontinues the product or activity that led to them. But what exactly is this strange condition of chromhidrosis, where colored sweat is actually produced within the body? Read on to find out.
Rainbow Sweat (and Where It Comes From)
Humans have two types of sweat glands on our bodies. Eccrine glands, found in their highest concentrations on the forehead, palms and soles, excrete mostly water and salts. These glands play the biggest role in the body's regulation of internal temperature, controlled by the hypothalamus. Apocrine glands excrete sweat that contains water, fats, byproducts of metabolic processes and wastes. These glands are found most highly concentrated around the genitals, underarms (axillae) and around the nipples and are triggered by emotional responses. Each type of sweat gland can be involved in chromhidrosis.
The amount, location and color of the sweat being excreted helps in diagnosis of the type of true chromhidrosis. Usually, apocrine chromhidrosis is seen in excretions on the face, the axillae and around the breasts [source: eMedicine]. Eccrine chromhidrosis may turn up on the palms or soles of the feet. Patients with eccrine chromhidrosis may excrete any color of sweat (as we'll see in a moment) and typically in large amounts. Cases of apocrine chromhidrosis typically involve a smaller amount of sweat, and it tends to appear around the nipples and underarms.
Apocrine chromhidrosis results in only yellow, green, blue, black and brown sweat. Here's why: The culprit behind apocrine chromhidrosis is lipofuscin. This is a pigment that is produced as a byproduct of the oxidization of lipids (fats) in some types of cells. Lipofuscin can be produced in the apocrine glands, and when it occurs in high enough concentration, it can color the sweat that's excreted by these glands.
When colored sweat is excreted as yellow, green or blue, diagnosing apocrine chromhidrosis is made simple. Physicians can examine the sweat and clothing stained with colored sweat under a Wood's lamp (an ultraviolet or black light). The lipofuscins phosphoresce in the light, revealing the cause. It becomes more problematic when the sweat is brown or black because, although the sweat is colored by lipofuscins, they've been highly oxidized when they reach that pigment and don't fluoresce under a black light.
To diagnose eccrine chromhidrosis (which is rarer than the apocrine variety), a patient history is a physician's best tool. In most cases, this type of chromhidrosis is the result of an intrusion of a foreign dye or pigment that the patient has ingested. The nurse from the last page was diagnosed with chromhidrosis resulting from a fondness of a particular packaged food that contained a tomato powder and paprika. It wasn't until her doctors questioned her that they were able to compare the food to samples of her colored sweat and identify the culprit. The ingredients were water-soluble and were being excreted by her eccrine glands.
Treating Chromhidrosis, from Red Peppers to Toxins
When doctors diagnose patients with chromhidrosis, the news will come with the assurance that the condition is benign; it's painless and it doesn't lead to any other maladies. If the patient asks how to treat it, however, he or she should forgive the physician for shrugging his or her shoulders. The first case of chromhidrosis was documented in 1709, and there haven't been many since. The mystery continues; in 2008, the first case of a patient with orange sweat was documented [source: Wyrick, et al]. Because of the rarity of chromhidrosis, the etiology (underlying causes) of the condition are unknown.
Treatment for eccrine chromhidrosis is relatively easy. Once a physician has identified the foreign agent responsible for the pigment, simply discontinuing exposure to it should cause the condition to disappear over time.
This isn't the case with apocrine chromhidrosis, though. Since medicine hasn't been able to conclude why lipofuscins might build up in the glands, it can't stem their concentration. This hasn't stopped physicians from trying some treatments, at times with mixed success. The best science has come up with is slowing the excretion of sweat.
One treatment that's shown some positive results is capsaicin, a synthesized version of a derivative of the red pepper plant. It's a topical cream most often used for pain relief in arthritis. By slowing the uptake of substance P, a neurotransmitter that's important in the sweat production in apocrine glands, some use of capsaicin has been effective in slowing chromhidrosis.
Other dermatologists and physicians have turned to botulinum, the neurotoxin used in the drugs Botox and Myobloc. The toxin also affects the neurotransmitters that cause sweat to be produced by eccrine and apocrine glands. Again, like capsaicin, there's been mixed results from the use of botulinum.
Ultimately, going after the glands themselves appears to be a chromhidrosis sufferer's best bet. One method is manually or chemically expressing the sweat glands that are producing colored sweat. In other words, the glands are forced to sweat, clearing out the offending lipofuscins and giving the patient relief. This relief isn't long-lasting, however -- the sweat usually comes back in a couple of days. The only proven treatment at effectively stopping chromhidrosis is the physical removal of the pigmented glands.
Related HowStuffWorks Articles
- Baker, Donald J., M.D. and Heymann, Warren R., M.D. "Eccrine and apocrine glands." American Academy of Dermatology.http://www.aad.org/education/students/glands.htm
- Branakin, Benjamin, et al. "Bilateral facial apocrine chromhidrosis." Journal of Drugs in Dermatology. March-April 2004.http://findarticles.com/p/articles/mi_m0PDG/is_2_3/ai_115505671/
- Briggs, Tracey Wong. "Sweat is nature's way of handling heat." USA Today. May 17, 2005.http://www.usatoday.com/weather/resources/basics/wsweat.htm
- Griffith, Joan R., M.D., M.H.A. "Isolated areolar apocrine chromhidrosis." Pediatrics. January 3, 2005.http://pediatrics.aappublications.org/cgi/content/full/115/2/e239
- HyperhidrosisWeb. "How sweat glands work." Accessed September 16, 2009.http://www.hyperhidrosisweb.com/sweat-glands-work.html
- Kim, June, M.D. "Chromhidrosis." eMedicine. December 9, 2008.http://emedicine.medscape.com/article/1072254-overview
- Lauchli, S., M.D. and Burg, G., M.D. "Treatment of hyperhidrosis with botulinum toxin A." Skin Therapy Letter. 2003.http://www.skintherapyletter.com/2003/8.7/1.html
- Musel, Andrea. "Chromhidrosis and pseudochromhidrosis." DermatologyReview.com Journal. October 2005.http://dermatologyreview.org/journal/chromo.pdf
- The Mayo Clinic. "Capsaicin (topical route)." June 1, 2009.http://www.mayoclinic.com/health/drug-information/DR600303
- Wyrick, K., et al. "Atypical chromhidrosis: a case report of orange sweat." Cutis. February 2008.http://www.ncbi.nlm.nih.gov/pubmed/18441771