A bump on the lip often prompts concern, but most lesions are benign, relating to common issues like viral infection, minor trauma, or simple anatomical variations. Understanding the characteristics of these bumps provides helpful context, though self-diagnosis is nearly impossible. This guide explores the most frequent causes of lip bumps and their typical presentations.
Bumps Caused by Viruses and Infections
The most frequent infectious cause of a lip bump is the Herpes Simplex Virus Type 1 (HSV-1), commonly known as a cold sore. An outbreak typically begins with a tingling, itching, or burning sensation before any visible bump appears. This is followed quickly by a cluster of small, painful, fluid-filled blisters, usually on the outer border of the lip. The blisters eventually rupture, creating shallow, open sores that dry out and form a hard, yellowish-brown crust before healing, a process that can take up to two weeks. The virus is highly contagious, especially when blisters are present, and spreads through close personal contact.
Other pathogens can also cause lip lesions. Impetigo is a bacterial skin infection that often affects the area around the mouth and nose, manifesting as reddish sores that burst and leave a characteristic honey-colored crust. This highly contagious condition is most common in children and requires antibiotic treatment. A fungal infection like oral thrush, caused by an overgrowth of Candida albicans, typically presents as creamy white patches that look similar to cottage cheese. These patches may appear on the inner lip or corners of the mouth and can be scraped away.
Physical Injury and Fluid-Filled Bumps
Bumps arising from physical injury often relate to minor trauma affecting the small, mucus-producing salivary glands beneath the lip surface. The most common example is a mucocele, a soft swelling that usually appears on the inner surface of the lower lip. A mucocele forms when the duct of a minor salivary gland is severed or blocked, often due to habits like lip biting, causing mucus to leak into the surrounding connective tissue.
This trapped mucus creates a smooth, dome-shaped cyst. Superficial mucoceles may appear translucent or bluish due to the thin covering tissue, while deeper ones may match the surrounding mucosa. Many mucoceles rupture spontaneously, releasing the mucus and resolving within a few weeks, but they frequently recur if the underlying trauma continues. Simple trauma, such as accidentally biting the lip or a minor burn, causes localized swelling that is usually painful and resolves quickly.
Common Harmless Lip Bumps
Some lip bumps are not caused by infection or injury but are normal anatomical variations or common benign sores. Fordyce spots are a frequent finding, appearing as small, painless, white or yellowish dots that are slightly raised and most noticeable around the vermillion border of the lips. These are enlarged sebaceous glands—the glands that produce oil—and are considered a normal part of the anatomy.
Another common type of bump is a canker sore, or aphthous ulcer, which is frequently confused with a cold sore but is different. Canker sores develop inside the mouth, often on the inner lip or cheek lining, and are not contagious. They are typically singular, painful, round or oval ulcers with a white or grayish center and a distinct red border. Unlike cold sores, which appear on the outside of the lip, the exact cause of canker sores is unclear, though they are often linked to stress, minor injury, or certain foods.
Knowing When to See a Doctor
While most lip bumps are benign and resolve without intervention, certain characteristics signal the need for professional medical evaluation. A bump that persists for longer than two to three weeks without any sign of healing or regression should be examined by a doctor or dentist. Rapid changes in the bump’s size, shape, or color are concerning and warrant prompt attention.
Bleeding that occurs spontaneously, or a bump that feels firm and hard to the touch are important red flags. Additionally, look for associated systemic symptoms, such as a persistent fever, unexplained weight loss, or swollen lymph nodes in the neck or jaw area. These persistent or rapidly changing symptoms must be evaluated quickly to rule out rare but serious conditions, including oral cancer.