It is common to mistake an inflamed sore at the corner of the mouth for a cold sore, but this confusion can lead to incorrect treatment. Angular cheilitis (AC) is frequently mistaken for a cold sore (herpes labialis) because of its location and similar appearance of redness and irritation. However, AC and cold sores are fundamentally different conditions with distinct causes and characteristics. Understanding the difference is important for receiving the right care. The distinction lies primarily in their origin—one is an inflammatory condition, and the other is a viral infection.
What Angular Cheilitis Is
Angular cheilitis is a localized inflammatory skin condition that affects the oral commissures, the corners of the mouth where the upper and lower lips meet. This condition manifests as areas of redness, inflammation, cracking, and fissuring, sometimes accompanied by crusting or scaling. It may occur on one side of the mouth (unilateral) or both sides (bilateral). Recurring exposure to moisture, often from saliva pooling, causes a breakdown of the skin barrier. This moist environment creates a favorable setting for microbes to grow, leading to irritation.
The Key Difference: Causes and Contagion
The most significant difference between the two conditions is their underlying cause and whether they are contagious. Angular cheilitis is typically a polymicrobial infection or inflammatory response, often involving opportunistic overgrowth of Candida yeast, which is naturally present in the mouth. Bacterial species, such as Staphylococcus aureus, can also contribute to the inflammation or cause a secondary infection. This condition is generally not contagious because it is caused by the overgrowth of microbes already present on the skin or due to environmental factors.
In contrast, cold sores are caused exclusively by the highly contagious Herpes Simplex Virus type 1 (HSV-1). HSV-1 is a viral infection that, once contracted, remains dormant within the nerve cells for life. Flare-ups are triggered by factors like stress, illness, or sun exposure, causing the virus to reactivate. Cold sores can be easily transmitted through direct contact with the lesion, such as kissing or sharing utensils, especially when the fluid-filled blisters are present.
Angular cheilitis can also be a symptom of systemic issues, including nutritional deficiencies, particularly a lack of B vitamins or iron. Other precipitating factors include misaligned dentures, frequent lip licking, or conditions that cause drooling, leading to constant moisture exposure. Since AC is not transmitted from person to person but develops from a combination of irritation and microbial overgrowth, it requires a different approach to diagnosis and management than a viral condition.
Differentiating Symptoms and Appearance
Observing the specific appearance and progression of the lesion offers a practical way to distinguish between the two conditions. Angular cheilitis is characterized by fissures and cracks that are strictly confined to the corners of the mouth. The affected skin often appears red, inflamed, and may have a crusty or scaly texture, and it is usually painful when opening the mouth. The sores in AC do not typically progress through the distinct stages of blistering and weeping seen in cold sores.
Cold sores typically begin with a prodromal phase of tingling, burning, or itching sensation before any visible lesion appears. Within 24 to 48 hours, they develop into small, distinct clusters of fluid-filled blisters, known as vesicles, which are highly characteristic of an HSV-1 infection. These blisters eventually rupture, weep fluid, crust over, and then heal, and they can appear anywhere on the lips or around the mouth, not just the corners. The presence of these small, fluid-filled blisters is the hallmark of an active cold sore outbreak.
Effective Treatment for Angular Cheilitis
Treatment for angular cheilitis focuses on reducing inflammation, eradicating the secondary infection, and addressing the underlying cause. Treatment often begins with the application of a protective barrier ointment, such as petroleum jelly, to keep the corners of the mouth dry and prevent further irritation from saliva. If a fungal infection is suspected, a topical antifungal cream is typically prescribed; alternatively, if bacteria is the cause, a topical antibiotic ointment, such as mupirocin, may be necessary. For significant inflammation or redness, a low-potency topical steroid may be used for a short duration to reduce swelling and discomfort. If a nutritional deficiency is identified, dietary changes or vitamin and iron supplementation will be advised to prevent recurrence.