A venous lake is a common, acquired vascular lesion that often appears on the lips and other sun-exposed areas of the body. While generally harmless, the appearance of a dark spot can be concerning, leading many people to seek medical clarification and treatment options. This article provides a comprehensive overview of venous lakes, covering their cause, diagnosis, and various modern removal techniques available.
Defining Venous Lakes on the Lip
A venous lake is a benign, acquired vascular lesion, which is a permanent dilation of a small vein (venule) near the skin’s surface. These lesions typically present as a soft, compressible papule, or raised bump, measuring between 0.2 and 1 centimeter in diameter. They are characteristically dark blue, purple, or sometimes almost black due to the presence of deoxygenated blood within the dilated vessel.
The most common location for a venous lake is the lower lip, particularly along the vermilion border, but they can also be found on the earlobes, face, neck, or upper trunk. Despite their dark color, they are non-cancerous and generally asymptomatic, meaning they do not cause pain or discomfort.
Cause and Risk Factors
The primary cause of a venous lake is closely linked to chronic, cumulative sun exposure over a person’s lifetime. Ultraviolet (UV) radiation is thought to damage the collagen and elastin fibers in the skin and the walls of superficial blood vessels. This damage leads to the weakening and subsequent dilation of the venule, allowing it to expand and become permanently congested with blood, forming the characteristic lesion.
This condition is overwhelmingly a feature of aging, most commonly seen in people over the age of 50, reflecting the long-term effect of sun damage. Other contributing factors may include minor trauma or injury to the lip, such as lip biting, and a history of smoking.
Medical Assessment and Confirmation
A medical assessment is important because the dark coloration of a venous lake can visually mimic more serious pigmented lesions, such as melanoma. Diagnosis typically begins with a clinical visual inspection by a healthcare provider to note the lesion’s color, size, and location. This is often followed by a simple, non-invasive procedure called diascopy, which is highly indicative of a vascular lesion.
During diascopy, a glass slide or dermatoscope is pressed firmly against the lesion. A venous lake will temporarily blanch or empty of its dark color because the pressure forces the blood out of the dilated venule. This distinct blanching confirms the vascular nature of the lesion and helps rule out non-vascular conditions. Dermoscopy, which uses a specialized magnified lens, will show a characteristic structureless blue or purple appearance.
A biopsy, which involves surgically removing a small piece of tissue for laboratory analysis, is generally not required for diagnosis. However, a biopsy may be performed if the lesion does not blanch, if its appearance is atypical, or if the clinician suspects a malignancy, like nodular melanoma, cannot be definitively ruled out. The primary goal of the assessment is always to ensure the lesion is benign.
Treatment Options for Removal
Since a venous lake is benign, treatment is usually sought for cosmetic reasons or if the lesion frequently bleeds due to minor trauma. Laser therapy has emerged as the preferred treatment method, considered the gold standard due to its precision and minimal risk of scarring. This procedure works by directing a specific wavelength of light, which is absorbed by the blood within the lesion.
The laser energy is converted into heat, causing the walls of the dilated venule to collapse and coagulate. This process leads to the body naturally reabsorbing the damaged tissue. The Nd:YAG laser (1,064 nm wavelength) is particularly effective because its longer wavelength allows for deeper penetration, often achieving complete clearance in a single session. A Pulsed Dye Laser (PDL) is also used, sometimes in combination with the Nd:YAG laser, especially for smaller lesions.
Alternative Removal Methods
Alternative removal methods include cryotherapy, which involves freezing the lesion with liquid nitrogen. While straightforward, cryotherapy carries a slightly higher risk of scarring or changes in skin pigmentation compared to laser treatment. Sclerotherapy, which injects a solution like polidocanol directly into the lesion to cause it to clot and shrink, is effective for larger lesions. Surgical excision is typically reserved for cases where other treatments have failed or the lesion is unusually large, as it inevitably leaves a small scar.