Syphilis is a bacterial infection caused by the organism Treponema pallidum, most commonly transmitted through sexual contact. The infection begins with distinct skin lesions that change in appearance as the disease progresses through its stages. Understanding what these lesions look like is important for recognizing a potential infection and seeking medical care. This guide focuses on the bumps, sores, and rashes that appear during the early course of the disease.
The Primary Lesion
The first visible sign of infection is a sore known as a chancre, which typically forms where the bacteria entered the body. This lesion usually appears between 10 and 90 days after exposure. The chancre begins as a small, raised, red papule that quickly evolves into a firm, round, and often solitary ulceration.
A hallmark feature of the chancre is that it is usually painless, often causing it to go unnoticed, especially in inconspicuous locations. The sore has a clean base and a raised, indurated, or hardened border, giving it a distinctive rubbery feel. Although most commonly found on the genitals, a chancre can also develop on the anus, rectum, lips, or inside the mouth.
While the classic description is a single, painless ulcer, some people may develop multiple lesions, and about one-third of chancres may be slightly painful. If left untreated, the chancre will spontaneously heal within three to six weeks, often without leaving a scar. However, the disappearance of the sore does not mean the infection is cured; the bacteria has simply moved deeper into the body.
Secondary Stage Skin Manifestations
If the primary infection is not treated, it progresses to the secondary stage, characterized by systemic bacterial spread and widespread skin issues. The most common feature is a non-itchy skin rash that can manifest in several ways, often starting on the trunk. This rash typically appears as rough, reddish-brown spots, which may be subtle or present as small, solid, flat, or slightly raised lesions.
A highly characteristic sign is the involvement of the palms and soles of the feet, which differentiates it from many other rashes. The spots on the palms and soles are usually reddish-brown or copper-colored and may involve slight scaling. The overall appearance can be highly varied, leading to syphilis being known as the “great imitator” of other skin conditions.
Another manifestation in the secondary phase is the appearance of Condylomata lata in warm, moist areas, such as the groin, under the arms, or around the anus and genitals. These lesions are flat-topped, broad-based, raised papules that can be pink or grayish-white with a velvety, moist surface. Condylomata lata are highly infectious and can sometimes be mistaken for genital warts.
Key Characteristics for Identification
The primary chancre is classically firm and indurated, a quality sometimes referred to as “cartilaginous” hardness. This feature helps distinguish the lesions associated with syphilis from the bumps and sores of other skin conditions. The absence of significant pain or tenderness in the chancre is an important feature, setting it apart from painful sores often caused by other infections.
The widespread rash of the secondary stage is notable for its general lack of itchiness, a characteristic that differentiates it from common allergic or fungal skin rashes. Both the primary sore and the secondary rash contain high concentrations of the Treponema pallidum bacteria, making them extremely infectious upon direct contact.
A deceptive aspect of the disease is the spontaneous resolution of these symptoms, which can happen even without medical treatment. The chancre heals on its own, and the secondary rash fades away. However, this self-resolution does not mean the infection is cured; instead, the organism enters a latent phase where it continues to spread and can progress to cause serious, long-term damage to organs like the heart and brain years later.
Immediate Next Steps
If you notice any of these described skin changes, particularly a painless sore or an unusual, non-itchy rash on your palms or soles, consult a healthcare provider immediately. Syphilis is easily diagnosed with a simple blood test, which detects antibodies the immune system produces in response to the infection. Fluid taken directly from a sore can also be examined to confirm the presence of the bacteria.
The infection is highly treatable and curable, especially in its early stages, using antibiotics. The preferred treatment is an injection of penicillin, which is highly effective at eliminating the bacteria. Completing the full course of treatment is necessary to ensure the infection is completely cleared and to prevent progression to the more dangerous late stages. Furthermore, informing past and current sexual partners is a public health responsibility that allows them to get tested and treated, which is an important step in limiting the spread of the infection.