Country Doc

Cold Sore or Pimple?

I could see the panic in his eyes. “What is it doc? Is it herpes?”  Running through his mind were worries of what to tell his wife. Where did I get it. Or did I get it from my wife? Has she been faithful? Is she going to think I have not been faithful. Is this going to be an ongoing problem the rest of my life?


In my opinion the fear attached to herpes is a little overblown, but it can be a real nuisance especially if it is genital herpes. In this article I will only discuss how to differentiate herpes from a common pimple. I have had a number of patients come to see me for this reassurance, so let me show you how to differentiate the two.

Let’s learn a medical term. (Do not panic, a big word is coming.)  Herpetiform.  Herpetiform is a medical descriptive term for a rash having the appearance of clusters of blisters. There are only a few rashes that appear as clusters of blisters. One is herpes simplex (cold sores). Shingles (herpes zoster) is another. Other “herpetiform” rashes are pretty rare. So the first step in evaluating a rash where herpes is the concern is to look for clusters of blisters. If it is on the lip, and is painful and is a single cluster (walks like a duck, quacks like a duck) you are most likely dealing with herpes simplex (cold sore). The reason I said it needs to be a single cluster is because shingles can look the same, but shingles will almost always have multiple clusters. (I will be writing an article about shingles in the future.) Another thing to look for is the location of the blisters. Usually with cold sores the clusters of blisters will be very near the border of the colored part of the lip and the skin of the face, called the vermillion border. The photo on the left is an excellent example of a typical cold sore. One possible confusing element though is that these blisters can easily break. The fluid contained is watery and clear. If the blisters break you will be left with a superficial erosion or ulcer like the picture on the right.


Pimples are plugged up oil glands that become infected. So usually, there is a small nodular area with a “white head” or pustule on top.  If you gently press the nodule the pustule will rupture and the fluid expressed will be thick and creamy colored.

I hope this helps you to tell the difference between pimples and cold sores.


Disclaimer:The information presented here and in other articles on this website is meant for general information only, and not for specific treatment recommendations. Nothing contained or offered by, on or through should be construed as medical advice or relied upon for medical diagnosis or treatment Speak with your physician or healthcare provider for more information on this topic. This is copyrighted material ©2011, all rights reserved


  1. Why is it all cold sore pics look tiny compared to mine? Mine are always hugeeeee! I've been using prevent cold sores to help reduce the amount of times I get them but they can still be massive!

    • Thanks for the comment James. The size of cold sores can vary tremendously. Larger cold sores are usually much more painful and more difficult to clear up. As time passes they will usually become smaller and less painful and occur less frequently.

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