Treating a lip infection depends on what’s causing it, since the most common culprits (a virus, a fungus, or bacteria) each require different approaches. Most lip infections fall into one of three categories: cold sores caused by herpes simplex virus, cracked and infected corners of the mouth (angular cheilitis), or bacterial infections from cuts or cracked skin. Identifying which type you’re dealing with is the first step toward the right treatment.
Cold Sores (Herpes Simplex Virus)
Cold sores are the most common lip infection. They appear as clusters of small, fluid-filled blisters, usually on or near the lip border, and are caused by herpes simplex virus type 1. The first outbreak tends to be the worst, with subsequent ones becoming milder over time. You’ll typically feel a tingling or burning sensation a day or two before the blisters appear, and that early window is the best time to start treatment.
Prescription antiviral medications are the most effective option. Valacyclovir, taken by mouth, can shorten an outbreak by one to two days when started at the first sign of tingling. For people who get frequent outbreaks, daily suppressive therapy with a lower dose can reduce how often they return. Acyclovir works similarly and is available in both oral and topical forms.
Over-the-counter docosanol cream (sold as Abreva) is the main nonprescription antiviral for cold sores. It works best when applied at the very first tingle, five times a day until the sore heals. It’s less potent than prescription antivirals but can still reduce healing time by roughly a day compared to doing nothing.
While you wait for the sore to heal, avoid touching the blisters, kissing, or sharing utensils. Cold sores are contagious from the moment you feel tingling until the scab falls off completely.
Infected Corners of the Mouth
Angular cheilitis looks different from a cold sore. Instead of blisters, you get red, cracked, sometimes oozing skin right at one or both corners of your mouth. It’s often caused by a yeast (Candida) overgrowth, sometimes combined with bacteria. Saliva pooling in the skin folds at the corners of the mouth creates a warm, moist environment where fungus thrives.
The standard treatment is a topical antifungal cream or ointment, sometimes paired with an antibacterial agent. A combination product containing an antifungal like nystatin and an antibacterial like mupirocin, applied in a thin layer to the corners of the mouth two to three times daily for about two weeks, is a common prescription approach. Some formulations also include a mild steroid to calm inflammation faster.
Between applications, keeping the area dry and applying a barrier ointment like petroleum jelly helps prevent saliva from re-irritating the cracked skin. If you wear dentures, poor fit is one of the most common triggers for angular cheilitis, since it changes how saliva flows around your mouth. Nutritional deficiencies in iron, zinc, or B vitamins can also make you more susceptible.
Bacterial Lip Infections
Bacteria, particularly group A streptococcus and staphylococcus, can infect the lips through small cuts, cracked skin, or after picking at a cold sore. A bacterial lip infection often looks like a spreading area of redness, warmth, and swelling, sometimes with yellowish crusting or pus. It may feel tender or throb.
Mild, superficial bacterial infections on the lip can sometimes be managed with a topical antibiotic ointment applied three times daily. If the redness is spreading, you have a fever, or the swelling is getting worse rather than better over two to three days, oral antibiotics are typically needed. Bacterial infections around the mouth can progress quickly because of the rich blood supply to the face, so worsening symptoms shouldn’t be ignored.
Home Care That Helps Any Lip Infection
Regardless of the cause, a few supportive measures can reduce discomfort and promote healing. A warm saline compress is one of the simplest. To make a sterile saline solution at home, boil 1 cup (250 mL) of tap water for 15 minutes with a lid on, let it cool to room temperature, then stir in half a teaspoon of non-iodized salt. Pour what you need into a separate clean cup (don’t dip anything into the storage container), soak a clean cloth, and hold it gently against the affected area for five to ten minutes. Refrigerate the remaining solution and discard it after 24 hours, or immediately if it turns cloudy.
Other practical steps that apply broadly:
- Keep lips moisturized with plain petroleum jelly or a fragrance-free balm. Dry, cracked skin is more vulnerable to infection and slower to heal.
- Avoid picking or peeling scabs or flaking skin. This introduces new bacteria and delays recovery.
- Skip irritating products like flavored lip balms, mouthwashes with alcohol, or lipsticks while the infection is active. These can worsen inflammation or trigger allergic contact reactions that mimic infection.
- Use a clean towel each time you pat the area dry. Reusing towels can reintroduce bacteria or fungus.
Infection vs. Allergic Reaction
Not every red, swollen, or peeling lip is infected. Allergic contact cheilitis, caused by a reaction to lip products, toothpaste ingredients, or even certain foods, can look very similar. The key differences: allergic reactions tend to affect both lips symmetrically, cause itching more than pain, and improve when you stop using the triggering product. Infections are more likely to produce blisters, pus, crusting, or cracking concentrated in one spot, and they don’t improve just by switching products.
Eczema on the lips (eczematous cheilitis) is another common mimic, especially if you have eczema elsewhere on your body. It causes dry, scaly, sometimes cracked lips that cycle between flaring and improving. Unlike an infection, it responds to gentle moisturizers and mild steroid ointments rather than antifungals or antibiotics. If your lip symptoms keep coming back despite treatment, the cause may not be infectious at all.