What is coining (Gua sha)?

Front with lesions.

A 46-year-old Vietnamese female with history of Churg-Strauss syndrome was seen for a flare-up and had the above skin changes. Based on the characteristics pattern can you diagnose the cause of this skin rash? Front and back images show (1).

(Answer below…)






What is coining?

Coining is a traditional techniques used to treat illnesses since ancient times that is widely practiced in China (also called Gua sha) and other South East Asian countries such as, Indonesia (referred to as Kerikan) Vietnam (referred to as Cao gio). The intention of coining is to rid the body of so called “heatiness and “negative energies” (2).


How is coining it done?

Coining is performed by taking a hard object with a smooth edge such as a coin and rubbing it along the skin in linear fashion until the a bruise is present. This can be painful as the bigger the bruise, the more effective this practice it thought to be.


What are the characteristic lesions of coining? What other exam findings should you look for to confirm coining?

Since coining is causing a bruise (i.e. blood under the skin), the lesions should not be blanchable (that is, when you press the redness does not go away). Usually, linear lines with spaces between the lines should be present. No petechia or other skin findings should be noted between these lines (unless there’s another cause for rash). Along with looking for petechia, check the oral mucosa and retina for hemorrhages. Also, exam for splenomegaly and hepatomegaly to look for underlying issues with the blood lines. In regions where dengue fever is endemic, consider this in your differential. The tourniquet test may be of value.

Back with lesions.

What serious the complications of coining?

For the most part, coining is considered to be pretty safe, although it may be painful! Camphor toxicity as been reported in one case (4). Given the bruising can be significant, coining is not recommended for anyone taking antiplatelet/anticoagulant medications or have issues with coagulation or platelet activity (e.g. Von Willebrand’s Disease). While no infections have been reported, it is highly recommended that sterile material used for this technique.


Hello!!!! Can’t I simply figure this out from the history?

Yes! Of course! The history is always very important. However, understanding the details of coining and it’s characteristic exam can be important for many reasons. Sometimes, the patient is unable to give a good history, either due to language barriers or mental status. Also, as coining often brings concern for child or elder abuse in physicians not aware of this practice, it’s important to be able to differentiate between the two. Finally, underlying diseases may be causing a rash while your patient presents with coining. Being able to tell what’s from disease and what’s not, can be very helpful!

Another example of coining (5).

Another example of coining (6).


  1. This case was obtained from Clinical Case Reports article What is the diagnosis for this rash?
  2. AK Tan and PS Mallika. Coining: An Ancient Treatment Widely Practiced Among Asians. Malays Fam Physician. 2011; 6(2-3): 97–98.
  3. https://en.wikipedia.org/wiki/Gua_sha
  4. Schneir ABClark RF. Coin rubbing and camphor intoxication. JAMA. 2002 Sep 25;288(12):1471;
  5. Image via Bradwesley69 from Wikipedia
  6. Image via Jugana Loder from Widipedia

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