A sudden change in the color of the vulva, the external genital area, often causes alarm, but this discoloration can stem from a wide range of reasons, from completely normal physiological responses to underlying health conditions. The appearance of a purplish or dark hue is frequently a result of changes in local blood flow or the body’s hormonal environment. While a majority of color shifts are benign and temporary, others may signal the need for medical investigation. Understanding the different categories of causes is the first step in determining the significance of this color change.
Benign Causes Related to Blood Flow and Hormones
The most common reasons for the vulva to appear purplish or darker are directly linked to increased blood volume in the pelvic region. This phenomenon is known as vascular engorgement, where the blood vessels dilate and become filled with deoxygenated blood, which appears blue or purple beneath the skin’s surface. A temporary example of this is seen during sexual arousal, where the surge of blood causes the labia minora and clitoris to swell and deepen in color, often to a reddish-purple or wine shade, before quickly returning to normal pigmentation.
Hormonal fluctuations can also cause a more sustained change in pigmentation due to their effect on blood flow and melanocytes, the cells that produce pigment. During pregnancy, the significant increase in estrogen and progesterone levels triggers a rise in blood volume throughout the body, including the pelvic organs. This leads to a distinct bluish-violet discoloration of the vulva and cervix, a well-documented sign known as Chadwick’s Sign, which can be observed as early as six to eight weeks into gestation.
The skin in the genital area is highly sensitive to hormonal shifts. Similar but less dramatic darkening can occur with cyclic hormonal variations, such as around the menstrual period or with the use of hormonal contraceptives. The general darkening of the vulva with age is also a normal process, often due to years of hormonal exposure combined with minor friction, leading to hyperpigmentation.
Causes Related to Localized Injury and Vascular Issues
Physical trauma to the delicate vulvar tissue can easily result in localized purple discoloration, presenting as a bruise or hematoma. Minor impacts, such as those from vigorous sexual activity, falls, or sustained pressure from activities like cycling, can rupture small blood vessels beneath the skin. The resulting bruise appears dark or purplish as blood pools and breaks down, and it will typically resolve on its own within a few days or weeks.
A more chronic vascular cause is the presence of vulvar varicosities, which are varicose veins that form on the external genitalia. These appear as soft, twisted, and bulging veins that are distinctly blue or purple due to pooled blood. Varicosities are often exacerbated by the increased blood volume and pressure experienced during pregnancy, but they can also occur in people with pelvic venous disorders.
These enlarged veins are caused by weakened vein walls and faulty valves that struggle to return blood from the lower body back to the heart, causing blood to collect. While they are usually harmless and often disappear on their own after childbirth, they can sometimes cause a feeling of heaviness, fullness, or pain in the vulvar area.
Underlying Dermatological Conditions and Infections
When the purple hue is persistent and accompanied by changes in skin texture, it may indicate an underlying inflammatory or dermatological condition. Lichen Planus (LP) is an autoimmune inflammatory disorder that can affect the skin and mucous membranes, including the vulva. LP classically presents with a violaceous coloration.
The erosive form of vulvar LP is more common and causes painful, raw, red, or dusky-red patches, often surrounded by white, lacy streaks. Chronic inflammation from LP can also lead to architectural changes, such as scarring or fusion of the labia minora. Other inflammatory conditions, such as Zoon vulvitis, can also present with a chronic, dusky red or bluish discoloration resulting from irritation and a specific inflammatory response in the skin.
Certain infections can also cause profound inflammation that manifests as a purple or dark red color. Severe localized infections like cellulitis, which is a deep bacterial skin infection, cause intense swelling and inflammation that can give the skin a red-to-purplish appearance. While less common, deep fungal infections can also lead to a dusky hue. These infections are typically accompanied by symptoms like warmth, tenderness, and rapid swelling, differentiating them from chronic inflammatory disorders.
Systemic and Medication-Related Causes
Rarely, systemic health issues or medication reactions can cause changes in pigmentation that may appear purplish or dark brown. Conditions that affect the body’s hormonal balance, such as Addison’s disease, can stimulate melanocyte activity, leading to generalized hyperpigmentation that includes the vulva. Certain medications, particularly some antibiotics or anti-malarial drugs, can also cause drug-induced pigmentation changes in the skin and mucous membranes.
Determining When Medical Attention is Necessary
While many causes of vulvar darkening are benign, a healthcare provider should evaluate any color change that is new, persistent, or concerning. Seek medical attention if the purple discoloration does not resolve within a few days or if it appears without an obvious cause, such as pregnancy or recent trauma.
Accompanying symptoms indicate a need for prompt diagnosis. Consult a professional immediately if you experience:
- The sudden onset of severe or rapidly worsening pain, significant swelling, or a fever.
- Discharge with a foul odor or bleeding that is not menstrual.
- Open sores and ulcers on the vulva.
- Intense itching, a burning sensation, or changes in skin texture like thickening or scaling.