Papular Acneform Eruption With Mucositis

The Diagnosis: Syphilis

Histopathology revealed psoriasiform hyperplasia, endothelial cell swelling, and a brisk lichenoid inflammation with plasma cells (Figure, A). There also was pustular folliculitis in association with well-formed granulomatous inflammation and a prominent number of plasma cells (Figure, B). Treponema pallidum immunostaining showed numerous organisms in the epidermal and follicular epithelium. Rapid plasma reagin was found to be positive with a titer of 1:128. Evaluation for neurosyphilis through lumbar puncture was negative; the patient also was HIV negative. All of our patient’s skin lesions cleared after a 3-week course of weekly intramuscular benzathine G injections. Due to his substantial clinical improvement, the patient was subsequently lost to follow-up.

Histopathology of an indurated cystic papule on the torso. A, Psoriasiform hyperplasia, lichenoid inflammation with plasma cells, and endothelial cell swelling were present (H&E, original magnification ×12). B, Pustular folliculitis and granulomatous inflammation with plasma cells also were noted (H&E, original magnification ×12).

Syphilis, an infectious disease caused by the spirochete bacterium T pallidum, has a well-known natural history defined by various stages classically categorized as primary, secondary, latent, or late (tertiary).¹ The classic lesion in primary syphilis is the chancre, a painless ulcer with raised borders that develops within approximately 3 weeks following the initial inoculation.² Secondary syphilis manifests with mucocutaneous findings in up to 97% of patients, and untreated patients develop secondary syphilis at a rate of approximately 25%.³ Although mucocutaneous findings in secondary syphilis can vary widely, patients most commonly develop a diffuse maculopapular exanthem, and 40% develop mucosal findings including genital ulcers, mucous patches, and condylomata lata.¹ In latent syphilis, there is seroreactivity, but otherwise there are no clinical symptoms. A clear symptomatic history of prior primary or secondary syphilis may be known or unknown. Latent syphilis is divided into early and late phases, and the World Health Organization designates 2 years after the first suspected exposure as the cutoff point for early and late latency.⁴ During the first 4 years of latent syphilis, patients may exhibit mucocutaneous relapses. Our patient denied any sexual activity for more than 3 years prior to presentation. Because of the start of iatrogenic immunosuppression during this period, this case was classified as late latent syphilis with mucocutaneous reactivation.

Behçet disease was included within the differential diagnosis but is characterized by multiorgan systemic vasculitis that causes various mucocutaneous findings including aphthous ulcers, papulopustular lesions, and genital ulcers.⁵ Histopathologic features are nonspecific, and the clinical finding of recurrent genital and oral ulceration should be present for diagnosis. This disease predominantly occurs in East Asian or Mediterranean populations and is otherwise rare in White individuals.

SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome is a rare disorder consisting of skin, joint, and bone manifestations.⁶ Severe acne generally is accompanied by palmoplantar pustulosis along with pain and joint tenderness involving the anterior chest and axial skeleton, both of which were absent in our patient.

Pustular psoriasis can be localized or generalized. Localized presentations frequently are acral and may be associated with a variable degree of nail dystrophy and arthritis. Generalized presentations are characterized by hyperemic, well-defined patches with variable numbers of pustules.⁷ The pustules are the consequence of exuberate neutrophilic exocytosis into the epidermis and are nonfollicular.

Steroid-induced acne may be considered in the proper clinical setting of an acneform eruption with a prior history of systemic steroid treatment. However, additional findings of mucositis would not be expected, and although our patient was prescribed prednisone from his primary care physician prior to presentation to our clinic, this medication was given after the onset of the cutaneous eruption.

Syphilis commonly is referred to as the great mimicker due to its potential diverse morphologic presentations, which can involve acneform eruptions, though rare.⁸ In the setting of mucositis, generalized acneform eruptions should raise suspicion for the possibility of syphilis, even in the absence of other more classic cutaneous features.