Actinomycetoma with systemic features: A warning sign for immunosuppression?

This is the authors' abstract. We don't add key points for this paper.

Case presentationA 32-year-old man was referred to our Dermatology Outpatient Unit with the clinical suspicion of sporotrichosis.At the age of 8, he had suffered a penetrating injury to his right foot, which remained as a painless nodule for years.One year before his outpatient appointment, the nodule progressively increased in size and ulcerated, and in the last 6 months, he began to experience night sweats, a low-grade fever, a 12-kg weight loss, and malaise.On examination, he had a foul-smelling and painful tumefaction with multiple nodules, fistulae, and purulent discharge, on the medial arch of his right foot (Fig 1A).He was pyrexial (37.9˚C), tachycardic (heart rate 126), but otherwise, other physical signs were unremarkable.The differential diagnoses considered for the skin lesion were dermatofibrosarcoma protuberans, amelanotic melanoma, Kaposi's sarcoma, and actinomycetoma.Exams were performed (biochemistry screen, a full blood count, and a chest X-ray).Amoxicillin clavulanate was initiated, and a punch biopsy of the lesion was done.The patient remained febrile and did not gain weight despite 3 weeks of antibiotics.Chest X-ray showed an enlarged mediastinum (Fig 2A).He was admitted to hospital for further investigation and treatment.Full blood count showed hemoglobin of 5.7 g/dL, 12,250 white blood cells/mm 3 , and lymphocytes of 2,082 cells/mm 3 ; C-reactive protein was 21.78 mg/L (reference value < 0.3); liver and kidney function tests were normal.Blood cultures and serological tests for HIV, toxoplasmosis, syphilis, cytomegalovirus, and hepatitis B and C were all negative.Because he was unwell and hypotensive on admission, Key Learning Points• Actinomycetoma is a chronic infection usually affecting the subcutaneous tissues of the lower limbs.• If systemic signs accompany the localized infection, an underlying immunosuppressive condition should be considered.• The inclusion of mycetoma in the WHO list of neglected diseases will hopefully increase awareness of this neglected disease.