A Crusted Plaque on the Right Nipple FREE

A healthy 27-year-old heterosexual man presents with a crusted plaque on his right nipple. The lesion formed gradually over a week after a bite during sexual intercourse and has persisted for a month. The patient reports that over the following 2 to 3 weeks, no significant change in size or morphology of this lesion occurred. The lesion is not painful; neither fever nor associated systemic symptoms are noted. Now, 1 month later, the patient presents with a generalized asymptomatic skin eruption. Physical examination reveals generalized pink macules on the trunk and extremities (Figure 1A). A crusted, erythematous plaque is noted over the enlarged right nipple (Figure 1B).

Chancre of the nipple with secondary syphilis

C. Perform a screening test for syphilis.

The key clinical feature is to recognize the association between the crusted nipple lesion and the subsequent development of a generalized macular rash after sexual contact. Physicians should include syphilis in the differential diagnosis, not just treat the lesion as a human bite, even though the nipple is not a common site for syphilitic chancre.

Primary syphilis chancres typically develop 1 to 3 weeks after exposure.¹ Although secondary syphilis usually presents 2 to 6 weeks after resolution of the chancre, considerable overlap exists between these stages.^1- 2 A primary syphilitic chancre typically occurs in the genital area.¹ However, approximately 5% to 10% of chancres are extragenital, mainly involving oral and anal mucosa.^1,3 Chin, tonsil, ear, neck, fingers, chest, and arms are among less commonly reported sites.¹ Extragenital chancre of the anus usually develops after anal intercourse in homosexual men.^1,3 There are only a few reports of nipple chancres, which usually develop following a bite.^3- 5Treponema pallidum can penetrate the mucosal surface but not intact skin. Minor skin trauma during sexual contact may facilitate the entry of T pallidum into a host.⁵

Extragenital chancres are often misdiagnosed due to the lack of consideration of sexually transmitted diseases for lesions not involving the genitalia and mucosa. Additionally, unlike in the genitalia, lesions on fingers, tongue, and anus are often painful.¹ The reasons for the pain are unknown, although secondary infections and antecedent trauma have been reported in some patients.¹ The variable and atypical clinical appearance of extragenital chancre frequently makes the diagnosis more difficult. The differential diagnosis of a crusted, erosive nipple lesion includes syphilis (chancre), nipple eczema, cellulitis, nontuberculous mycobacterial infection, erosive adenomatosis of the nipple, squamous cell carcinoma, and mammary Paget disease.

Serologic tests, such as rapid plasma reagin and T pallidum hemagglutination (TPHA), and clinical examination are usually sufficient to make the diagnosis of syphilis. In cases of atypical presentation or a negative rapid plasma reagin result, a skin biopsy can help confirm the diagnosis or rule out other concurrent diseases. Tzanck smear and potassium hydroxide preparation are useful for the diagnosis of herpetic and fungal infection, respectively, but they provide limited information for diagnosing syphilis. Ultrasonography may be helpful to evaluate space-occupying lesions such as abscesses and neoplasms, but it does not contribute further to the final diagnosis.

The therapy is the same for both genital and extragenital syphilitic chancres and secondary syphilis: intramuscular administration of benzathine penicillin G, 2.4 million units in a single dose.¹

This patient received a rapid plasma reagin test and skin biopsy at his first visit to confirm the exact cause of the nipple lesion. The laboratory investigations showed a positive rapid plasma reagin result (titer, 1:64) and TPHA (titer, 1:2560). Enzyme-linked immunoassay test for human immunodeficiency virus was negative. Skin biopsy demonstrated epidermal hyperplasia with focal ulceration and a dense, superficial dermal infiltration. Under higher magnification, there was a lichenoid infiltrate composed of lymphoplasma and histiocytic cells around the dermoepidermal junction and perivascular areas (Figure 2A). Immunohistochemistry demonstrated numerous spirochetes in the epidermis and dermis (Figure 2B). Both the nipple lesion and the generalized pink macules gradually resolved after 2 weekly intramuscular injections of benzathine penicillin G, 2.4 million units.