Doctor Fish--Cure for Psoriasis?

In my book, From Alzheimer's to Zebrafish: Eclectic Science and Regulatory Stories, there are a number of insects, bacteria and animals described that have some similarities in that all have or may have some medical application.¹ There was one essay included on zebrafish used in genetic screening and drug discovery.

At the time that article was written, I was firmly convinced that no other aquatic species could be included on this distinguished list. This despite the fact that I knew there were literature references to wound-cleaning fish and with earlier evidence that a small fish called Garra rufa had been used in an experiment to treat individuals with skin diseases like psoriasis.²

I recently discovered that Garra rufa species have been employed to perform fish pedicures. The fish consume dead skin on people's feet and leave newer skin exposed-thus the name "doctor" or "nibble" fish.³ Fish pedicures fortunately have not been implicated in any associated illnesses, but there have been a number of outbreaks of bacterial infections related to nail salon foot baths. They have resulted in wound problems, septicemia, boils and scarring. Because of these problems, more than 10 states have banned the use of fish pedicures.⁴

Banning is based on at least one of the following reasons:

• The fish pedicure tubs cannot be sufficiently cleaned between customers when the fish are present.
• The fish themselves cannot be disinfected or sanitized between customers. Due to the cost of the fish, salon owners are likely to use the same fish multiple times with different customers, which increases the risk of spreading infection.
• Chinese Chinchin, another species of fish often mislabeled as Garra rufa and used in fish pedicures, grows teeth and can draw blood, increasing the risk of infection.
• According to the US Fish and Wildlife Service, Garra rufa could pose a threat to native plant and animal life if released into the wild because the fish is not native to the US.
• Fish pedicures do not meet the legal definition of a pedicure.
• The fish must be starved to eat skin, which might be considered animal cruelty.

The last bullet point is of particular concern to the Royal Society for the Prevention of Cruelty to Animals (RSPCA), the UK's leading animal welfare charity. The society believes overcrowding fish in a small volume of water will lead to increased concentrations of ammonia, which will affect the health of the fish.

Chemicals used to clean or disinfect tanks or to clean client's feet prior to treatment may be toxic to the fish. In addition, salon staff where pedicures are offered may not be properly trained to adequately ensure the welfare of the fish. RSPCA has reminded practitioners that they have a responsibility for the welfare of the fish under the UK's Animal Welfare Act of 2006.⁵

Description

"Doctor fish" is the nickname given to the species Garra rufa. The species occurs in the river basins of the Northern and Central Middle East, mainly in Turkey, Syria, Iraq and Iran. Although Garra rufa are native to various Middle Eastern countries, they are largely concentrated within the river beds and hot springs in Turkey.

It is thought that their unique healing properties were discovered in Turkey. This earned the Garra rufa its nickname.

Doctor Fish Spas

During the 1960s, health spas were built near the habitat of the Garra rufa so visitors could benefit from the foot therapy.⁶ In 2006, doctor fish spas opened in Hakone, Japan, and in Umag, Croatia, where the fish are used to clean the bathers.

There are also spas in resorts in China, Belgium, the Netherlands, South Korea, Singapore, Bosnia-Herzegovina, Hungary, Slovakia, India, Thailand, Cambodia, Indonesia, Malaysia, the Philippines, Hong Kong, the Czech Republic, Spain, France and Norway. The procedure is legal in Quebec, with a few clinics in Montreal.

In 2010, the first UK spa opened in Sheffield, England. However, the UK's Health Protection Branch issued a statement on 17 October 2011, warning fish foot spas could potentially spread blood borne viruses such as hepatitis and HIV if infected patients bleed into the spa water.⁷

Ichthyotherapy

According to Wikipedia, ichthyotherapy can be defined as the use of freshwater or marine organisms as agents of skin wound/condition cleansing.⁸ The name comes from the Greek ichthys, meaning fish.

The history of such treatment in traditional medicine is sparsely documented. There is widespread use of such fish in India, particularly in rural areas. The benefits were first observed in Kangal, Turkey-therefore Garra rufa is also called the Kangal fish.

Patients suffering from psoriasis have benefited from the doctor fish treatment, which involves lying in the ponds and letting the fish eat the scales and loose skin on the affected areas. In fact, the popularity of the treatment for skin conditions led to Kangal becoming a health resort.

In one published study, 67 patients diagnosed with psoriasis underwent three weeks of ichthyotherapy in combination with short-term ultraviolet A (UVA) sunbed radiation at an outpatient treatment facility. Patients were required to stay in treatment tubs for two hours a day. Each patient was allocated a personal bathing tub, and the fish only came in contact with a single patient.

The participants reported substantial satisfaction with the treatment. There was a reported mean remission period of more than eight months, and 87.5% of the patients reported a favorable outcome when compared to other previously tried therapies.

The response rate was comparable to other studies where mail surveys were used. There were no significant adverse events.⁹ The study, of course, was limited by the relatively small number of patients treated and by lack of a control group. Randomized trials would be needed to compare the ichthyotherapy treatment with controls and to assess treatment with standardized health-related quality of life questionnaires.

The study is certainly not definitive. However, in light of the widespread distribution of psoriasis and the fact there is no cure, the finding is promising. This is particularly true because of the favorable safety profile.

Moreover, there is currently no simple, safe, and invariably effective treatment. For this reason, many patients rely on conventional pharmacological methods or try alternative and complementary treatment modalities.¹⁰

Possible Mechanisms of Action

Several mechanisms have been suggested regarding the observed efficacy of ichthyotherapy. One obvious mechanism is the physical contact with the fish, which feed on the desquamating skin, thus leading to a rapid reduction in the scales of psoriasis. The fish seem to prefer affected instead of healthy skin.

Another suggested mechanism could be that the simultaneous removal of scales by the fish facilitated the penetration of UV rays to the dermis. This exposure of lesions may explain the better outcome of combined ichthyotherapy/UVA treatment when compared to the poor results of UVA sunbed treatment alone.¹¹

Final Thoughts

Someone unfamiliar with the nuances of medical device law might say doctor fish could never be approved for use in US. The idea would appear preposterous.

On the other hand, the same thought could have been rendered for leeches several years ago. They, however, were deemed to be medical devices and eventually cleared by the 510(k) process.¹²

According to a June 2004 FDA Talk Paper, leeches met the definition of a device because they are articles intended to "diagnose, cure, treat, prevent or mitigate a disease or condition, or to affect a function or structure of the body that does not achieve its primary effect through a chemical action and is not metabolized."¹³

Leeches are indicated to help heal skin grafts by removing blood pooled under the graft and to restore blood circulation in blocked veins by removing pooled blood. The French company submitting the 510(k) did not include a predicate device in its submission, as leeches were unclassified.¹⁴

Will another company be brave enough to try the same strategy for doctor fish? Would patients be brave enough to undergo treatment? I have my doubts.

References

1. Sherman M. From Alzheimer's to Zebrafish: Eclectic Science and Regulatory Stories. Rockville, MD; Regulatory Affairs Professional Society; 2012.
2. Grassberger M, Hoch W. "Ichthyotherapy as Alternative Treatment for Patients with Psoriasis: A Pilot Study." Evidence-Based Complementary and Alternative Medicine. 2006; 3(4):483-8.
3. Vugia DJ et al. "Mycobacteria in nail salon whirlpool footbaths, California." Emerging Infectious Diseases. 2005; 11(4):616-8.
4. Centers for Disease Control and Prevention. "Fish pedicures and fish spas." CDC website. www.cdc.gov/healthywater/hygeine/body/fish_pedicures.html. Accessed 24 June 2012.
5. Kelly A. "RESPONSE: Why it's wrong to use Garra rufa fish in pedicures." The Ecologist. The Ecologist website. www.theecologist.org/blogs_and_comments/commentators/other_comments/899341/response_why_its_wrong_to_use_garra_rufa_fish_in_pedicures.html. Accessed 26 July 2012.
6. "Fish Therapy (ichthyotherapy)." The Health Clinic. www.thehealthclinic.eu/eng/wellness-hotels/special-treatments. Accessed 28 August 2012.
7. Ibid.
8. Wikipedia. "Doctor Fish". http://en.wikipedia.org/wiki/Doctor_fish. Accessed 27 August 2012.
9. Op cit 2.
10. Warwick D, Warwick J. "The doctor fish-a cure for psoriasis". Lancet. 1989; 335:1093-4.
11. Turner RJ et al. "A controlled study of ultraviolet A sunbed treatment of psoriasis. British Journal of Rheumatology. 2000; 143:957-63.
12. US Food and Drug Administration. Talk Paper. FDA Clears Medicinal Leeches for Marketing. 28 June 2004.
13. K040187, Ricarimpex SAS, cleared on 21 June 2004.
14. Op cit 12.