Dental Local Anesthesia and Ehlers Danlos Syndrome

Ehlers Danlos Syndrome is a group of similar inherited disorders that adversely affect the connective tissue. Patients with this disease experience problems in the skin, joints, blood vessels, and other areas. In addition, some disorders within the syndrome also make the individual resistant to local anesthesia.

Unfortunately very few dentists are aware of this phenomenon. And in addition, there are patients out there with undiagnosed Ehlers Danlos, as well as patients with EDS who are not aware of the issues with local anesthesia. What happens? The patient ends up having a very unpleasant time at the dentist with both the dentist and patient trying to figure out what is going on!

About Ehlers Danlos Syndrome

Ehlers Danlos and dental local anestheticIt is not the point of this blog post to talk about the Syndrome in great detail. There are plenty of other sites out there that accomplish this. However, to understand how this affects dentistry and the dreaded “novocaine shot,” you need to know a bit about the disease.

Ehlers Danlos affects connective tissue. Connective tissue is basically the “glue” that holds other tissue and organs together. Specifially, there are defects with the production of collagen, which is the major protein in connective tissue. While there are six major types of EDS, they are all generally characterized by hypermobile joints (joints that can move way beyond what would be considered normal), joint pain, fragile and easily bruised skin, and other findings.

Not all of the genes responsible for Ehlers Danlos are known and there is active research into all parts of this syndrome.

Why Does Local Anesthesia Not Always Work?

First, it needs to be mentioned that not all of the six types of EDS make the patient resistant to dental local anesthetic. Based on research (here and here), it appears that Type III – Hypermobility is the one in which this phenomenon is seen.

dental injections don't always work in Ehlers Danlos

For those with some types of Ehlers Danlos, you will need MANY injections of very specific anesthetics for effective local anesthesia.

Unfortunately, the mechanism behind why the local anesthesia is less effective is not well understood. The current theory focuses on the “looseness” of the connective tissue. Since the connective tissue is defective, it is very easy for the local anesthetic to quickly move away from the site that is being anesthetized. Stated another way, the connective tissue barriers that hold the local anesthesia in place for the duration of the dental procedure are weak and easily broken.

The end result is that the patient is not sufficiently numb for the dental procedure, leading to pain. Patients get confused, discouraged, angry, and ultimately avoid the dentist, which then makes things even worse down the road.

What Should Dental Patients Do?

Ehler Danlos hypermobility which can affect dental local anesthesia

If you can do this with your thumb, you may have Ehlers Danlos.

As a dentist who treats patients in private practice, I am disappointed that this issue is not well known in the dental community. Ask most dentists and unfortunately, most will not be aware of this. In fact, in what is considered the bible of dental local anesthesia (A Handbook of Local Anesthesia by Stanley Malamed), there is no mention of phenomenon (I searched the 6th edition).

Here are some tips:

  1. Find a dentist who has experience with Ehlers Danlos. There is nothing wrong with calling an office and asking if the dentist is familiar with EDS and this local anesthetic phenomenon.
  2. Identify yourself early on as having Ehlers Danlos to the hygienist and dentist.
  3. Find an opportunity to meet with the dentist in advance of any procedure requiring local anesthetic to review the plan (remember that the office may have to order a special type of local anesthetic).
  4. Consider taking a medication beforehand to relax you.
  5. Be ready for a longer than normal appointment.
  6. At the completion of the appointment, especially if it was successful, ask the dentist for detailed records on the local anesthesia (what local anesthetic, how much administered, where administered, etc.)

In some cases, nitrous oxide and/or IV sedation may be necessary to complement the local anesthesia.

My own experience treating patients with Ehlers Danlos has shown that most of the time, we can achieve local anesthesia. I attribute my success to knowing the pharmacology of local anesthetics as well as other injection techniques. To use a pun based on EDS, with a little “flexibility” in selecting local anesthetics and injection sites, we can nearly always succeed!


  1. Joanne McKenzie says:

    I read about Ehlers Danlos syndrome in your blog. I think this is a really informative blog. Every time what a local anesthesia do does not work because they use local product. A dental patients always follow the instruction what his/her doctor instruct to do. For more information you can follow our website.

  2. Elizabeth Darden says:

    Ehlers Danlos syndrome (EDS) is the name for a group of rare inherited conditions that affect connective tissue. Connective tissues provide support in skin, tendons, ligaments, blood vessels, internal organs and bones. Some times the dentists use less quantity for local anesthesia so the procedure don’t work properly. Specially the quality of the products make difference in the procedure.

  3. Thanks for promoting our EDS Awareness Logo for We have helped to form >100 local EDS support groups and hosted > 65 live EDS related webinars by EDS experts. See webinar recordings at:

  4. Alisha Franco says:

    I had a tooth pulled about 5 years ago before I knew I had ehlers Danlos syndrome Hypermobility and the dentist had to give me 4 shots before I could no longer feel anything. He was very mad at me and saying that I didn’t feel anything and it was in my head. I was crying and so scared. He said I was just feeling pressure but no pain. I knew I was feeling pain and I finally screamed and was feeling like II got pass out. My fave was so numb it was sagging when we were all done.
    Horrible experience!

    • Jennifer Duncan says:

      Alisha Franco…That is so my story too. I was ten and had to have 7 teeth extracted (3 were baby teeth ) and the anaesthetic worked for a bit but not for long. For the last three teeth I was not numb at all. The dentist was yelling at me, telling me I wasn’t in pain, just feeling pressure. And kept threatening me saying that he could give me another shot but it would have to go in my upper pallet and did I remember how much that hurt? Sometimes npvacane works for me and sometimes it doesn’t. Same dentist later had to fill a cavity for me and after two shots and I wasn’t numb, he grudgingly gave me a third. He didn’t put anything on topical on the gum. When he injected ,I screamed, and he said “You weren’t kidding, you really weren’t numb!”. This man put me off dentists for years!

      Finally found a dentist who worked well with me. She wasn’t familiar with EDS but before my first official appointment she learned about it and how it affected my oral health. Such a different experience!

  5. This is my entire dental experience life. I was diagnosed with type iii at the age of 34. You are. Genius

  6. Im not scared or anxious of dentists per se, but the reason I do get anxious is because I have never had a visit to the dentist where the injection has fully taken first time. And it usually wears off fast. Same with painkillers, I need a lot to even touch pain. Must be the way my liver metabolises things. I do have psoriasis and autoimmune issues and wonder if that has something to do with it. When I go to a new dentist it is always the same, they never listen and don’t believe me so Ihave to go through it all again each time. I have had to move around a lot you see and reliant upon NHS so if Im out of the catchment area I cannot keep the same dentist. Sigh… it is horrible having to feel pain every time. Sadly I don’t get a lot of choice on NHS – and too many of them are far from humble or nice.


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