What Causes Cold Sores and How are They Treated?

Rohit Kushwah

Medically Reviewed By Dr. Aarti Nehra

Cold sores, also known as fever blisters, are a prevalent viral infection characterized by small, fluid-filled blisters that emerge near the mouth or other facial regions. In uncommon instances, cold sores may manifest on the nose, fingers or inside the mouth. Typically appearing in clustered patches, these sores can endure for two weeks or more. Cold sores are highly contagious and can be transmitted through close contact, such as kissing, even when they are not visibly present. This article delves into the symptoms, causes and treatment of cold sores.

Cold Sores Causes

Cold sores are attributed to the herpes simplex virus, with two distinct types identified. Herpes simplex type 1 (HSV-1) is the primary cause of cold sores, while herpes simplex type 2 (HSV-2) typically leads to genital herpes. The appearance of the actual sores is comparable for both virus types, and it’s noteworthy that HSV-1 can cause genital sores, while HSV-2 can result in oral sores. Visible cold sores are contagious, and transmission can occur even when the sores are not apparent. Contracting the herpes simplex virus can happen through various means, such as kissing, sharing food, sharing cosmetics or engaging in oral sex.

Cold Sores Symptoms

Cold sores often present with noticeable symptoms, typically preceded by a tingling or burning sensation on the lips or face several days before the sore’s emergence. Commencing treatment during this initial phase is most effective. Once formed, a cold sore manifests as a raised, red blister filled with fluid, often painful and sensitive to touch. It is not uncommon for multiple sores to be present simultaneously. The cold sore persists for up to two weeks, remaining contagious until it forms a crust. The first occurrence of a cold sore might occur up to 20 days after contracting the herpes simplex virus.

During an outbreak, individuals may also experience additional cold sores symptoms, including muscle aches, fever and swollen lymph nodes. If any eye-related symptoms manifest during a cold sore outbreak, seeking immediate medical attention is crucial, as untreated herpes simplex virus infections can lead to permanent vision loss.

Cold Sore Treatment

Once infected with the herpes simplex virus, a cure is not there, but effective management is achievable. After the cold sores have healed, the virus remains dormant in the body, with the potential for reactivation, leading to the appearance of new sores (active stage). When cold sores do emerge, there are several treatment options available. These include:

Antiviral Creams

Antiviral creams available over the counter can help reduce the duration of a cold sore outbreak. Commonly used creams, like Soothelip and Zovirax, typically contain antiviral agents such as penciclovir or acyclovir. It is advisable to apply the cream to the affected area every 2-3 hours for a duration of 5 days.

Antiviral Medications

Several antiviral medications, such as acyclovir, valacyclovir and famciclovir, can be taken orally to manage cold sores. If a person experiences frequent outbreaks or has a weakened immune system, then a doctor may prescribe one of these medications. Typically taken once or twice a day, these medications can help shorten the duration of an outbreak and may prevent them from recurring.

Pain Relief

Over-the-counter pain relief options for cold sores often contain analgesics like lidocaine or benzocaine. While these medications do not expedite the healing process, they can alleviate discomfort. Some examples of pain relief medications for cold sores include Blistex, Cymex, Orajel and Anbesol. Alternatively, individuals may consider using ibuprofen (Advil) or acetaminophen (Tylenol) for pain relief.

Home Remedies

Following some home care tips can help manage cold sore symptoms. A few effective options for cold sore treatment at home include:

  • Ease symptoms by applying ice or using washcloths soaked in cold water over the sores.
  • Use a lip balm containing lemon extract, which can be a helpful cold sore remedy.
  • Taking lysine supplements regularly is associated with less frequent outbreaks for some individuals.
  • Apply aloe vera lip balm or aloe vera gel to cold sores three times a day. Aloe vera, the cooling gel found inside the leaves of the aloe plant, may bring relief.
  • While not a cure, applying petroleum jelly, such as Vaseline, can ease discomfort, prevent cracking and serve as a protective barrier against outside irritants.
  • Witch hazel, a natural astringent, may help dry out and heal cold sores due to its antiviral properties. Be cautious, as it may sting upon application.
  • Dab the affected area with diluted lavender, geranium or tea tree oil, which may have antiviral properties.


Cold sores can be painful and disruptive. While many individuals can manage outbreaks at home using over-the-counter or prescription treatments, those with weakened immune systems should consult a doctor if experiencing cold sores or other oral herpes symptoms. Recognizing early signs of an outbreak and initiating treatment promptly can be beneficial in managing and alleviating symptoms.

Rohit Kushwah


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