In the June 9, 2008 edition of "Archives of Internal Medicine," Northeastern Ohio University dermatologist Dr. Christina Cernik reports that cold sores are one of the most common complaints encountered by primary care physicians. Indeed, says Cernik, most American adults are infected with the herpes simplex virus that causes cold sores. However, several other viruses also cause skin conditions that look like cold sores. In most cases, a doctor can distinguish between cold sores and similar conditions on the basis of history and physical examination.
Canker Sores
The Academy of General Dentistry explains that location is the key to distinguishing between canker sores and cold sores. Although both can present as painful open sores with a loosely attached layer of white, grey or yellow tissue that doctors and dentists call a "pseudomembrane," canker sores only develop inside the mouth. By contrast, only about 5 percent of cold sores develop inside the mouth, according to Cernik, usually only during the first outbreak and, even then, they are still almost always accompanied by lesions outside the mouth, on the lips and sometimes the surrounding facial skin. Therefore, "cold sores" inside the mouth that occur more than once probably represent canker sores, although only a dentist or doctor can confirm the diagnosis.
Chicken Pox
In the 2008 edition of "Harrison's Principles of Internal Medicine," University of Alabama Professor Richard J. Whitley notes that the varicella-zoster virus that causes chicken pox belongs to the same family of viruses, known as herpesviridae, as herpes simplex. Chicken pox, like cold sores, causes painful or itchy blisters on the face and often inside the mouth. Unlike cold sores, however, chicken pox soon spreads to the trunk and, finally, the arms and legs. Cold sores rarely spread to these sites, except among people with a history of skin abrasions like wrestlers who develop mild friction injuries from contact with the mat, and people with skin problems like eczema.
Hand, Foot and Mouth Disease
Hand, foot and mouth disease is the common name for infections caused by some species of coxsackie and enteroviruses, according to National Institutes of Health virologist Dr. Jeffrey I. Cohen in the 2008 edition of "Harrison's Principles of Internal Medicine." Sores typically appear first and remain most extensive inside and outside the mouth, however shortly thereafter, patients also develop sores on the backs of the hand, sometimes spreading around to the palms. Other, less commonly involved skin sites include the buttocks, the soles of the feet, and the back of the throat, says Cohen. Like cold sores, hand, foot and mouth disease usually--but not always--strikes during childhood. Unlike cold sores, hand, foot and mouth disease does not recur.
References
- "Archives of Internal Medicine"; The Treatment of Herpes Simplex Infections; Dr. Christina Cernik; June 9, 2008
- "Harrison's Principles of Internal Medicine, 23rd Edition"; Dr. Anthony S. Fauci et al.; 2008
- Academy of General Dentistry: What Are Cold Sores?
- Academy of General Dentistry: Cold Sore vs. Canker Sore
