Primary syphilis - Anogenital in
Treponema pallidum can also cross the placenta and infect an unborn child, resulting in early congenital syphilis. See also late congenital syphilis.
In the primary stage of syphilis, a painless ulceration, or chancre, typically appears about 21 days after initial infection, often preceded by a firm, painless papule. In girls, the genital chancre is difficult to observe because of its location in the vagina or on the cervix.
The entire genital area is susceptible, including the anus and inside the urethra. Chancres are typically asymptomatic. If secondary erosion or fissuring occurs, they may be painful. Other symptoms may include bloody stool and rectal pain.
Chancres vary in size from a few millimeters to several centimeters. They have an incubation period of 10-90 days (average 21 days). The chancre lasts 3-6 weeks and heals spontaneously. All patients with primary syphilis will go on to develop secondary syphilis if the condition is left untreated. Secondary syphilis usually appears 3-10 weeks after the primary chancre and is characterized by a papulosquamous eruption and mucosal involvement, in some cases. Tertiary syphilis may appear months to years after secondary syphilis resolves and can involve the central nervous system (CNS), heart, bones, and skin.
Ocular screening (eg, slit lamp examination) is advised for patients with suspected or proven syphilis.
Childhood sexual abuse is a problem of epidemic proportions affecting children of all ages and economic and cultural backgrounds. There are few unambiguous diagnostic signs of sexual abuse, and they are present in only a minority of victims. They include objective evidence of characteristic genital trauma and the detection of specific STIs. The presence of semen, sperm, acid phosphatase, a positive serologic test for syphilis or HIV, and a positive culture for gonorrhea are considered absolute evidence of sexual abuse when congenital acquisition of the disease and transfusion-acquired HIV are excluded. Nonsexual transmission of syphilis from an infected parent to a child is rare, and sexual abuse should always be assumed until proven otherwise.
Related topics: ocular syphilis, endemic syphilis
A51.0 – Primary genital syphilis
266127002 – Primary syphilis
Differential Diagnosis & Pitfalls
Transmission through sexual abuse:
- Genital herpes simplex virus – Look for multiple small vesicles on an erythematous base; usually painful.
- Chancroid (Haemophilus ducreyi) – Multiple nonindurated ulcers with irregular, ragged undermined edges; very painful; yellow exudate commonly present.
- Lymphogranuloma venereum (Chlamydia trachomatis serovars L1-3) – Ulcers usually not observed but can be small, shallow, and painless; often transient.
- Granuloma inguinale (Klebsiella granulomatis) – Painless, extensive, and progressive; looks like granulation tissue.
- Ecthyma gangrenosum – Ulcers are necrotic and rapidly increase, commonly on extremities and trunk.
- Amebiasis – Starts as a vesicle that ulcerates; typically painful with undermined edges; can have purulent exudate.
- Genital trauma – Preceded by known insult; erosions are more geometric and painful.
- Fixed drug eruption – Red-brown papules or annular plaques; can progress to bullae and erosions mimicking syphilis. Recurrent lesions are always located at the same site.
- Behçet disease – Associated with recurrent oral ulceration, genital ulceration, and ocular abnormalities.
- Contact dermatitis – Preceded by exposure to irritant; progression to ulceration would be unusual and indicates severe disease.
- Calciphylaxis - May rarely present with tender ulceration on genital skin; occurs in patients with renal failure.