One of the more common problems encountered in dermatology practice is herpes simplex (also known as cold sores). Cold sores are caused by the herpes virus, either type one or type two. The virus enters the skin through some opening in the epidermis often secondary to trauma. It then replicates in the skin and within a few days produces itching, tenderness and mild discomfort in the involved area. This is rapidly followed by swelling and redness. Within 24 to 48 hours, multiple grouped vesicles (blisters) appear. The vesicles soon become cloudy, then develop a purulent (pimple-like) character with subsequent erosion and crust formation. An enlargement and tenderness of a local or regional lymph node may develop simultaneously.
While this process is developing, the viral particles ascend the local cutaneous sensory nerve to its sensory ganglion. This is where the virus makes its permanent home. The nerve cell soon recognizes the foreign substance within its confines and mounts a local immune response that effectively inactivates the virus. However, the cell is unable to completely kill the virus or remove it from its confines.
Treating Herpes Simplex
There are a variety of topical therapies available for herpes simplex. If used immediately, as the cold sore develops, they may modify and possibly shorten the course of the disease. Unfortunately, the active ingredients do not penetrate well through the epidermis where the virus is actually proliferating. By the time the process is in full swing and vesiculation (blistering) is present, it is unlikely the medication will penetrate through the roof of the vesicle, through the fluid, and into the base of the blister to attack the virus.
There are at least six effective drugs for systemic therapy of the herpes simplex virus that are currently available. The key to successful therapy is to institute the medicine at the onset of the problem. Most patients who have had a cold sore in the past know when another one is coming. It invariably occurs at or around the area where the previous lesions had occurred and is preceded with burning, tingling, or puffiness. If the oral medications are started within 48 to 72 hours, the herpetic lesion will quickly resolve.
Will It Disappear Permanently?
The frustrating thing about herpes simplex, for both the patient and the provider, is that while the therapy is very effective at clearing the skin lesions, none of these medications penetrate into ganglionic nerve cells to kill the virus. The virus often reactivates and may recur anytime the body temperature is elevated (such as during colds, flu, pneumonia, sunburns, premenstruation, ovulation, or during emotionally stressful times). Herpes simplex can also be a significant problem for people who are immunosuppressed by leukemia, lymphomas, chemotherapy, and AIDS. There is also the risk of herpes developing in newborns at the time of delivery if the mother has the active disease. Patients with severe atopic or other generalized dermatitis are also at risk of developing extensive skin involvement with the herpes virus.
The actual cold sore lesions may occur singularly or with multiple lesions on any part of the body. They may also occur in a nerve distribution and can stimulate herpes zoster. Although lesions occurring above the waist are thought to be caused by herpes simplex type 1 and those lesions below the waist are caused by herpes simplex type 2, this theory can no longer be relied on. Culturing and typing is generally unnecessary because treatments for both types are basically the same.