Skin changes associated with sexually transmitted infections (STIs) are often referred to as “breakouts.” These manifestations include lesions, rashes, bumps, and sores that appear on or near the genitals, mouth, or other areas of the body. While understanding the visual differences between these symptoms offers insight, relying on appearance alone for a conclusion is impossible. Self-diagnosis is unreliable and risks misidentification and delayed care. If any new or unexplained skin change occurs, professional medical confirmation through testing is necessary to determine the cause and guide proper management.
Viral Causes: Blisters and Ulcers
One common cause of skin breakouts is the Herpes Simplex Virus (HSV), which typically results in clusters of small, fluid-filled lesions. Before the lesions appear, many people experience a localized tingling, burning, or itching sensation, known as the prodrome phase. The physical outbreak begins with the formation of multiple tiny, tense vesicles on a reddened patch of skin that are often quite painful.
These small blisters contain viral particles and eventually rupture, leaving behind shallow, tender ulcers or sores. Over a few days, these open sores dry out and form a yellowish crust before healing completely, usually without scarring. Outbreaks frequently occur in the genital area, including the vulva, penis, anus, and nearby skin, but can also manifest around the mouth. The virus remains dormant in nerve tissues and can reactivate periodically, causing recurrent outbreaks that are often shorter and less severe than the initial episode.
Bacterial Causes: Sores and Rashes
In contrast to the painful, clustered blisters caused by a virus, a bacterial infection like syphilis presents with different skin changes across its stages. The primary stage of syphilis begins with the appearance of a chancre, which is a firm, round, and typically painless sore at the initial point of infection. This sore often has a clean base and sharply defined borders, usually measuring one to two centimeters in diameter.
Because the chancre is usually painless and may be hidden inside the vagina, rectum, or mouth, it can easily go unnoticed. Even without treatment, this primary sore will heal on its own within three to six weeks, but the bacterial infection remains active. If the infection progresses to the secondary stage, a systemic skin rash develops, frequently characterized by reddish-brown spots. This rash is usually non-itchy and often involves the palms of the hands and soles of the feet, a classic finding for this stage.
Other Viral Manifestations: Warts and Bumps
Other viral infections can manifest as distinct growths rather than open sores or rashes, presenting as bumps or warts on the skin. Human Papillomavirus (HPV) is a common cause of genital warts, which are growths often described as flesh-colored and having a rough, cauliflower-like texture. These warts can appear as small, subtle bumps or may cluster together to form larger masses in the genital and anal regions.
Another viral cause of bumps is Molluscum Contagiosum, which results in small, firm, dome-shaped papules on the skin. These lesions are typically flesh-colored or pearly white and have a characteristic small indentation or dimple in the center, referred to as umbilication. Molluscum papules usually measure two to six millimeters in diameter and can occur in the genital area of adults through sexual contact.
Seeking Professional Diagnosis and Management
Any new or unusual skin change should prompt a consultation with a healthcare provider, such as a primary care physician, gynecologist, urologist, or staff at an STI clinic. The diagnostic process begins with a physical examination of the affected area and a detailed discussion of recent symptoms and sexual history. Specific laboratory tests are necessary to confirm the presence of an infection and correctly identify the causative agent.
If open sores or blisters are present, the provider may swab the fluid or tissue from the lesion for a nucleic acid amplification test (NAAT) to identify the virus or bacteria. Blood tests detect certain infections, such as later stages of syphilis or HIV, by looking for antibodies or antigens. Bacterial infections are typically treated with antibiotics, while viral infections are managed using antiviral medications to suppress outbreaks. Visible growths like warts or molluscum may require cryotherapy, topical treatments, or physical removal procedures.