The scrotal skin is not an uncommon site for a primary syphilitic lesion. The primary stage of syphilis is marked by the appearance of a single sore (chancre), approximately 21 days after exposure. The chancre is usually ﬁrm, round, small, and painless, lasts 3 to 6 weeks, and heals without treatment. Regardless of location, the syphilitic chancre is grossly the same (see Plate 2-23). It may occur at the penoscrotal junction with barrier contraceptives. Lesions of the scrotum, however, are much more common in later forms of syphilis, especially during early and late relapses. They appear during relapse within the ﬁrst 2 years but have been observed many years later as well. Anogenital cutaneous relapse occurs in 40% of cases and scrotal lesions occur in 25% of relapsing cases.
In secondary syphilis, scrotal lesions may occur with a generalized cutaneous, nonpruritic rash and mucous membrane manifestation. This stage usually appears several weeks after the chancre has healed. Secondary syphilis may also mimic many other cutaneous diseases, but the generalized rash characteristically appears on the palms and on the undersides of the feet. On the scrotum, this rash may resemble tinea cruris, lichen planus (see Plate 3-6), or can appear as papules similar to urticaria pigmentosa. Follicular, nodular, and pustular lesions are relatively rarely observed on the scrotum, as secondary syphilitic rashes are more often papular or annular in character. The moist papule is the most common syphilitic lesion found on the scrotum. Annular recurrences are also observed in untreated and insufﬁciently treated patients. Annular lesions are actually moist papules with raised circular ridges that are elevated about 0.5 mm from the surrounding skin and may be covered by a light scale that exudes serum. Later the papillae appear as glistening or translucent elevated rings where the skin is stretched. The lesions can be hidden within the scrotal skin folds. If the scrotum is stretched, annular and papular lesions become obvious. Annular lesions may also occur in the tertiary stage. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. These symptoms will resolve without treatment but will progress to the latent and possibly late stages of disease. The annular and papular forms of cutaneous secondary syphilis are often misdiagnosed. Papular lesions sometimes develop into ﬂat condylomata lata, with an eroded surface caused by nonspeciﬁc hypertrophy of the epidermis. They can be associated with condyloma acuminata near the rectum and can be found in similar individuals at risk for sexually transmitted diseases. However, it is important to differentiate these two lesions: condyloma acuminata are dry, cauliﬂower-like, and bulky, whereas condyloma lata are smooth, moist, and ﬂat. It should be emphasized that scrotal lesions, even in relapsing syphilis, are infectious.
The latent stage of syphilis begins when primary and secondary symptoms disappear and this stage can last for years. The late stages of syphilis develop in about 15% of untreated patients and can appear 10 to 20 years after infection was acquired. In late-stage syphilis, signs and symptoms include difﬁculty coordinating muscle movements, paralysis, numbness, gradual blindness, and dementia. Ulceration on the scrotum in tertiary syphilis may occur from gummas of the testis and epididymis, which may become adherent to the overlying skin. Such chronic, indolent, and painless ulcers should not be confused with tuberculous ulcers, sarcoma, or necrotic teratoma, which cause similar manifestations. Lymphedema and mild pseudo-elephantiasis of the scrotum can results from obstruction of syphilitic inguinal lymph nodes.