man with sore throat

Doctors are taught that a really bad sore throat should be cultured to determine whether it is caused by a group A beta-hemolytic streptococcal infection (aka strep throat).

If the test comes back positive, the patient is treated with an antibiotic because untreated strep sometimes triggers rheumatic fever. If the test is negative, the patient is often sent home and told to wait for the discomfort to disappear.

Why Should You Worry About F-Throat?

Many physicians are not aware of another kind of sore throat caused by Fusobacterium necrophorum (aka F-throat). A study in the Annals of Internal Medicine (Feb. 17, 2015) suggests this F-throat infection is more common than strep throat among adolescents and young adults. It is not as easily diagnosed because the routine throat culture carried out in a doctor’s office will not catch it. Untreated, F-throat can cause severe illness or even death.

How Common is F-Throat?

The researchers recruited 312 students at a university health clinic who arrived complaining of a “sore throat.” The scientists used a sophisticated PCR (polymerase chain reaction) test to tell what kind of bacteria might be causing the sore throat symptoms. What they found was a game changer.

One fifth of the students had F-throat. Half as many (10 percent) had strep infections. What this means is that a surprisingly high number of sore throats in young adults are caused by F. necrophorum bacteria. In fact, it was the most common bacterium triggering sore throat symptoms in this college population.

Diagnostic Disaster

What this means is that current diagnostic practices will not catch this common and potentially deadly infection. Doctors have guidelines for treating strep throat. As far as we can tell, there are no guidelines for treating F-throat. That means that most physicians do not know what the best antibiotic treatment is for F-throat; that lack of knowledge could be disastrous.

Deadly Lemierre’s Disease from F-Throat

Let us tell you a story we heard from Lisa Sanders, MD. She writes the “Diagnosis” column for the New York Times Magazine. In one of her articles (and also in an interview on our radio show) she related the case of a 17-year-old boy who developed a fever and sore throat. Because he was so sick, his mother took him to the family physician promptly after his symptoms worsened.

The doctor diagnosed strep throat (without a culture) and prescribed a macrolide antibiotic called azithromycin (Zithromax, Zmax). It usually works well for strep throat. But instead of getting better, the young man continued to run a fever with shaking chills and his sore throat got substantially worse, localizing on one side of his neck.

The parents took him to the emergency room of the local hospital, but the ER physicians didn’t consider F-throat either. The antibiotics they prescribed didn’t work against F-throat. By the time the doctors figured out that the infection was caused by F. necrophorum and he had developed Lemierre Syndrome, it was too late. The young man died because of a misdiagnosis and inadequate treatment.

Should you be Worried about F-Throat?

Physicians have been taught that F-throat is relatively rare and that if it occurs it primarily affects teenagers or young adults up to the age of 30. But Lisa Sanders described a case of a 44-year-old mother who developed F. necrophorum. The only reason she was correctly diagnosed was because her ear, nose and throat specialist couldn’t figure out what was happening and consulted an infectious disease expert. This specialist recognized F-throat and recommended the antibiotic that saved her life.

The study in the Annals of Internal Medicine established that F-throat is twice as common as strep throat, at least in a college-age population. Although Lemierre syndrome is relatively rare, it is such a serious condition that it must be diagnosed promptly and treated correctly. Penicillin or metronidazole are more appropriate than antibiotics like azithromycin, ciprofloxacin, erythromycin or tetracycline.

How to Recognize F-Throat

As we have already described, the traditional diagnosis with a routine throat swab and culture is not going to catch F-throat. Clues to report to a physician include:

  • A bad sore throat that does not get better after a few days
  • A fever
  • Night sweats and shivering
  • Pus in the back of the throat
  • Swollen glands in the neck
  • Swelling in the neck, especially on one side

If you suspect that you or someone you love has F-throat, encourage your physician to consider this diagnosis. Make sure that she does her homework on Fusobacterium necrophorum and knows how to treat it appropriately.

Sinusitis and F. necrophorum:

The throat is not the only place this bad actor can show up. An article in The Pediatric Infectious Disease Journal (Jan. 31, 2018) discuses cases of serious sinusitis linked to F. necrophorum.

In one instance a 15-year-old young man ended up in the ER with:

“…acute altered mental status, photophobia, speech difficulty, right upper extremity weakness, and sinus pressure. For the past week, he had experienced headache, fever, and occasional emesis [vomiting].”

The infection had penetrated into his skull and brain. A brain scan after treatment showed the severity of the infection:

“CT one month later revealed new moth-eaten changes of the frontal bone, suggestive of chronic osteomyelitis. Paranasal sinuses were significantly improved and well aerated. The patient had neurologic recovery, with slight difficulty with speech and right hand coordination difficulty.”

Fortunately, this young man survived. The authors note that Fusobacterium can cause sinusitis without any symptoms of sore throat. It also means that physicians will need to be alert for this kind of infection since it requires a different antibiotic approach.

There is also evidence that the bacteria can invade the middle ear (The Pediatric Infectious Disease Journal, July, 2008). The authors note that:

“Inappropriate antibiotic treatment may seriously compromise clinical outcome.”

Beware Misdiagnosis:

Misdiagnosis can cause serious harm or death. Surprisingly, misdiagnosis is far more common than most people realize. Some experts estimate that diagnostic error rates are as high as 15 percent in clinical medicine.

You will read about the “Top 10 Reasons Why Doctors Screw Up Diagnoses” in our book, Top Screwups Doctors Make and How to Avoid Them. You will also discover the “Top 10 Questions to Ask to Reduce Diagnostic Disasters.” And you will find out the about the most common diagnostic errors to watch out for in Top Screwups.

Do not let F-throat or other common conditions go misdiagnosed. Protect yourself and those you love with knowledge.

Please share your own story below and vote at the top of this article.

Revised: 3/15/18

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  1. Dp
    Hamilton on

    Hello, and thanks so much for this page! My daughter one week ago complained of sore neck. The next day sore throat and a fever started. Took her to the doctor where he took throat culture and bloodworm. Prescribed Zithromax for 5 days by day 3 she was not any better, actually worse. The doctor changed antibiotic to amoxicillin clavulin. Thank God he did or we would be in big trouble. I told the doctor about f-throat and he agreed that’s what she had. Thanks.

  2. thai

    Parents and newer doctors also need to be aware of peri-tonsillar abscess. My teenage daughter almost died from this bacterial illness that swells the throat till it closes, which our ENT told us killed George Washington. The young ER doc sent us home when I took her in because she could not swallow any food, saying it was a virus and would get better. The next day, with fever, bedridden, unable to swallow anything, I took her to her regular, older pediatrician, who immediately recognized the illness, sent her across the hall to the ENT. He told us to meet him at the hospital in two hours because she needed immediate surgery. She was in the hospital several days, receiving hundreds of units of IV antibiotics for the infection which had become systemic. Don’t assume all doctors know the answers; trust your instincts!

  3. Rhonda

    I think you ought to take this information and inform the three major the news networks’ medical reporters so that the word about this can get out. Of course no one wants people to panic and flood emergency rooms and doctors offices when their illness might improve on its own, but still it is very very concerning!

  4. Vicki

    Interesting; but sounds like the study was conducted at one university. In one student population, where students can infect each other, I don’t think the numbers are shocking. I’d like to see a study of a broader and more random population.

  5. Wendy
    Rochester NY

    My daughter had repeated bouts of severe sore throat during her senior year in college. The college clinic considered hospitalizing her, as her HR was 120+ and she had a high fever. The rapid strep test always came back negative. After some research, I asked them to test her for Strep C infection, and to test her boyfriend (who was asymptomatic). Both came back positive. If I had known about F-throat, I would have insisted that they test her for that too.

    Shah M, Centor RM, Jennings M. Severe Acute Pharyngitis Caused by Group C Streptococcus. Journal of General Internal Medicine. 2007;22(2):272-274. doi:10.1007/s11606-006-0049-4.

  6. Kellie

    Back in March I was diagnosed with strep throat. Ever since I’ve had a reoccurring sore throat. I’m 18 & I had to miss my high school graduation due to how bad my symptoms were getting and I ended up in the hospital… They took blood, x rays, throat swabs and everything came back negative. After a few hours of steroids and liquid through an IV i felt a lot better and they said I must have had a viral infection that was getting worse…
    2 months later I got another sore throat only lasted a few days (wasn’t too bad) Then a few weeks later I got ANOTHER sore throats ended up in the hospital, they sent me home very fast with some antibiotics, 4 days of steroids, and some pain killers. My pain went away for 4 days and is now back. My ear hurts (per usual) my neck is swollen again and I’m missing out on a lot of things due to this, and it totally sucks..
    I’m going to see a specialist this week and will mention this article because I’m so SICK of being sick like this

  7. Diamond

    All diabetics, asthmatics and those who have immune deficiency disorders should be automatically tested for a range of throat infections if their illness persists for two weeks and is getting worse.

  8. Asima

    My 14 year old daughter has had her tonsils out quiet a few years ago. For the past year she keeps gettin sore throat with fever and the shivers and on and off sweats, I’m worried as she has previously been ill whn she was 3 had chemo for a year!! She see her consultant in manchester childrens hospital for on goin ear problems whn he check her throat he says it’s just red but no1 ever checks further so what do i do show this article 2 her consultant

  9. ICU-RN

    I am not only a parent, but also a RN. This is the first time I heard of F-Throat. My 14yr old daughter was swabbed for Strep and Mono today. Both came back negative, so the MD ordered blood work. Hopefully she improves soon. If not I will ask for further testing.
    Her throat looks horrible!!!

  10. Pam

    My daughter needs her tonsils out. She will be having the surgery in May. She is on antibiotic at the rate of at least once a month because of throat infections. Every time they test for Strep A or mono, it’s always negative. Sometimes the throat culture is even sent out, but it seems they only test for what they feel is common. As soon as my daughter gets off antibiotic she gets sick again with swollen lymph nodes, fever, white patches on the tonsils, and a lot of pain. I don’t feel that she is ever being prescribed what will really get rid of the bacteria that she has. My latest complaint would be a dr at the urgent care that we went to yesterday who didn’t examine my daughter and told her it’s usually strep A an tried to immediately prescribe Zithromax which causes my daughter to get extremely sick. The dr was upset that we wouldn’t allow something tht has been proven to make my daughter much sicker. He said he was going to find something different and the nurse came back and sai that Keflex had been ordered.

  11. William
    Springfield, MO

    This is a tempest in a teapot. I am a physician who has been in practice for 30 years and I have never seen a case of Lemierre’s syndrome, despite the fact that I am aware of the disease and have tested for it when the symptoms suggested. This suggests that fusobacterium infection does not need to be routinely tested for or routinely treated.

  12. Kathey

    my 21 year old son was told he had a virus and was sent home with steroids. The next day he twisted his leg and pulled his calf muscle. Within 48 hours he went to the ER because he thought he had a respiratory infection and a leg infection. While in the ER his temp spiked to 104 and his left lung collapsed. Finally after 5 days in ICU, multiple leg surgeries to remove the infection from his leg he was diagnosed with Lemierre’s Syndrome. He spent a total of 24 days in ICU and had a lung deportation. It was a nightmare. We are lucky that he survived.

  13. M. Storms M.D
    Marquette, Michigan

    The patients I had with this infection responded to Rocephin (ceftriaxone) or Unasyn (ampicillin/sulbactam).

  14. M. Storms M.D
    Marquette, Michigan

    I have had two patients present with Lemierre’s syndrome and they needed ICU care. They were clearly quite ill. But I don’t agree that all patients with a severe sore throat need antibiotics right off the bat. That would lead to an overuse of antibiotics. However, if a sore throat does not improve and the patient has worsening of symptoms overall, then this infection should be considered.

  15. Donna
    St. Louis, MO.

    Think this is very important information as Strep was commonly treated by Physicians with penicillin or like antibiotics, especially if pus present in throat.

    The emergence of F-Throat is very important development and calls for throat culture for differentiation of the two.

  16. Carla

    I have never heard of this. So glad I read this article. I imagine I will have to take it with me to a doctor in order to educate them should my son ever have a really bad sore throat. Thanks.

  17. Melinda

    This is the first I have ever heard of F-Throat. This is very helpful and important information to know as I have 4 children from ages 24-17. My 17 year old has a sore throat this week so this is a very timely article. She tested negative for strep on Monday . She had a severe sore throat until Thursday. Thankfully she is feeling better now. If not, I would be with her in the doctor’s office asking about F-throat with this article in hand. Thank you for alerting us about F-throat.

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