Not only monkeypox infection: Keratoderma blenorrhagicum

A 18-year-old man presented to our clinic with a 1-month history of genital, hand and trunk skin lesions that worsened progressively in the past 4 days, associated with mild fever, headache and sore throat. He reported unprotected sexual intercourse with two different partners in the past 2 months.

Physical examination revealed pustular lesions, erythematous crusty papules associated with erosion with collarette scales in the genital area and in the palmar surface of the hands bilaterally (Figure 1(a)). Also present was bilateral inguinal lymphadenopathy along with pharyngitis characterized on fiberoptic endoscopic evaluation by erythema and diffuse edema of the oropharynx and soft palate, a massively swollen uvula, and multiple punctate erosions in the hard palate region. No signs of exudate or ulceration were noted during the endoscopic examination (Figure 1(b) and (c)). To exclude monkeypox infection, PCR analysis was performed on throat and skin lesion swab but it resulted negative. Serologies for HIV, syphilis, HBV and HCV were also negative. PCR testing in urine and urethral swab was positive for Chlamydia trachomatis. Blood tests showed an increase in inflammatory markers (C-reactive protein 3.87 mg/dL) and a biopsy performed on a lesion of the palm of the hand showed a pustular psoriasis-like pattern. An ophthalmological and rheumatological examination did not reveal any pathology affecting the joints and/or the visual apparatus. Considering all the reports above, we diagnosed keratoderma blenorrhagicum.OPEN IN VIEWER

Antibiotic therapy with azithromycin was prescribed to treat Chlamydia trachomatis with clinical response.

Keratoderma blenorrhagicum is characterized by the presence of psoriasiform and vesicular pustular lesions mainly localized in the acral region that may precede or usually accompany other symptoms associated with Reiter’s syndrome.^1,2 These clinical features enter into the differential diagnosis with the typical lesions from monkeypox infection which is a zoonosis that occurs with mucocutaneous manifestations characterized by erythematous macules, umbilicated papules, painful vesicles and pustules progressing to indurated eschars with a predilection for genital, perianal and perioral or tonsillar areas; lymphadenopathy, prodromal symptoms, maculopapular rash and mucositis are also sometimes present.^3,4 The current monkeypox outbreak is an evolving situation, thus a better understanding of morphological, clinical and temporal features could help in prompt diagnosis of this infection. Therefore, it is important for the dermatologist to consider that similar lesions can be associated with different pathologies and to be able to quickly recognize and treat them adequately.