Strep is short for streptococcus, a family of ball-shaped bacteria. In the strep family, Group A beta-hemolytic strep is responsible for throat infections in humans that can have serious consequences like Glomerulonephritis (a kidney inflammation) and Rheumatic fever. When the bacteria itself is infected with a certain virus, the patient may have not only a sore throat but also a high fever and a diffuse bumpy or “sand-paper” rash that is called scarlet fever. The rash is caused by a toxin (poison) produced by the strep-infecting virus. The presence of scarlet fever indicates a higher chance of complications.

Only 5-10% of sore throats are caused by the Group A beta-hemolytic strep germ. A common patient complaint is “I think I have strep throat.” Often a family member, usually a child, was diagnosed with strep via a rapid (in the office) strep test. Now one of two situations exist.

In the first situation, the person coming to see me has symptoms, sore throat, painful swallowing, aching etc… They want to know do they have “strep”.

In the second, the person is asymptomatic or has a scratchy throat and is leaving town on business or vacation and does not want to get sick while they are gone. This is a legitimate concern, but I may not be able to prevent an illness. To help you understand how I sort this out is why I am writing this article.

Sorting it all out.

Here is what I am looking for to help me sort things out. There is a diagnostic tool I use called the McIsaac modified centor score. Using it helps me decide to treat empirically, that is, without other tests, or to do those tests to determine treatment.

On the McIsaac score, one point (+1) is given for each of the following:

Age less than 15 years - Fever over 100.4F (38 C) - Absence of cough - Tender/swollen lymph nodes in the neck - Swelling and or pus on the tonsils or back of the throat. +5 total points possible.

One point is subtracted if the patient is over 45 years.

Score roughly equates to risk of strep infection

The risk of strep is as follows:

score % +for strep

-1 1%

+1 10%

+2 17%

+3 35%

+4or5 51%

The strategy I employ is to test people if they have a score of 2 or 3 with a rapid test (in office, 10 minutes) or to culture them (more accurate but 3 days to results). I treat patients who test or culture positive for strep or who have McIssac scores of 4 or 5 with antibiotics.

What kind of antibiotic?

Penicillin has been the main therapy for strep throat for many years. It has several draw backs. It must be taken more than 2 times a day and more importantly penicillin and its derivatives like amoxicillin have a failure rate(don’t cure the infection) of 5 - 60% against strep. This depends on how often you have been treated with antibiotics in the past and how well you do with taking them. Ideally you take every dose of penicillin on time, on an empty stomach and haven’t had many treatments with antibiotics in the past. Under ideal circumstances bacterial resistance (resistance means an antibiotic won’t kill it) is around 5%. The more of those factors that vary from ideal, the greater the chance penicillin therapy will fail. A drug class called cephalosporins is preferred. Cephalexin (a first generation cephalosporin) is cheap, can be taken twice daily and is quite effective. If the patient is allergic to penicillin, there may be cross reactivity (you are allergic to other similar drugs) with cephalexin (Keflex). Third generation cephalosporins (like Omnicef and others) are effective, sometimes in less than 10 days therapy and usually don’t cross react with penecillin allergic patients. Cephalosporins have the advantage of being better absorbed in the presence of food. That there are no generic 3rd generation cephalosporins so they carry a higher copay and total price tag is their main disadvantage.

What else could it be?

If you score a one or less on the McIssac scale it is unlikely you have beta-hemolytic Group A strep causing your symptoms. So,what else causes such a severe sore throat? Mainly viruses. One of the worst is the Epstein bar virus that causes mononucleosis. Not only does it hurt, it causes fever and pus on the tonsils, swollen nodes (glands), saps your energy and lasts for weeks. Mononucleosis can not be cured with antibiotics. Some antibiotics make it worse and will cause a rash if you take them while you have “mono”. Other bacteria can cause a sore throat but are non-Group A strep. Herpes simplex or the “cold-sore” virus can cause herpetic sores in the throat and won’t respond to antibiotics. About 5% of sore throats are caused by the Herpes type 1 virus. Other viruses can cause pain, low fever and lots of small ulcers but again antibiotics can’t cure it and can make it worse.

What do you do when you are leaving town?

I negotiate with my patient. They have a score of 3, I did the culture but it won’t be ready for three days and they leave in two. If they are traveling within the state, I call them on their cell and tell them the results. If antibiotics are required, I call them in to a pharmacy near them. I have a number of patients that travel regularly outside the country. In that case I give them a prescription to fill, ask them to hold it. Either I or my assistant call their cell or I email them results. If results are positive they take the prescription, if not they hold it. I have to trust them just like they trust me.

The next time you go to your provider for a sore throat give them your symptoms not your diagnosis. Tell you provider when your symptoms started and whether suddenly or gradually. Tell each of the McIssac indicators you noted (fever, swollen “glands” etc… see above). Know your current medications and what you took for the symptoms (hopefully you did not take some “left-over” antibiotics). Provide a list of your habits like the amount you smoke each day and your health status (are you in great health, stressed from work, sick family members, divorce, death in your family etc…). I hope you don’t get a sore throat but if you do I hope this helps you get better and faster treatment.

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