If the attacks of cold sore have already occurred in you might most probable know what they are if they tend to return in your case. But if you or your children are candidates of primary infection of the herpes virus or your fever blister is taking more than one week to heal please see your doctor immediately.
The diagnosis of cold sores comes from the history given by the patient along the inspection of the skin of the patient. At times it is difficult to come to a certain diagnosis or confirm it.
Various lab procedures can be done to make or confirm the diagnosis of the cold sores if required.
Most of the times the appearance of the fever blisters itself leads to their diagnosis. Sometimes laboratory studies can be done to confirm the diagnosis by taking blood sample or the fluid from the fever blister to confirm the diagnosis of the cold sore infection. But this is usually only necessary in case of immunocompromised patients either due to HIV infection or the ones undergoing chemotherapy. The viral culture provides an excellent way of making and confirming the diagnosis but the process might take three to seven days after which the outbreak stage is over. The growth and lab culture of the virus is not very easy as at times the tests come out to be negative even in the presence of the virus. Commonly a positive result indicates the presence of HSV-1 infection in a patient. The latest tests available detect the virus under a microscope and provide quick trust worthy results usually in less than an hour of the sample reaching the lab. The virus is present in sufficient amount to be detected in the cell scrapings from the fever blister. The test can also differentiate between the type 1 and type 2 strain of the herpes virus.
The antibody present to the virus in the blood is also detected and serves as a medium to distinguish between the new and old or re-occurring infection.
Dentists also diagnose a large number of cases of cold sore in their daily dental practice.
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