Primary Mycobacteria tuberculosis following intralesional steroid

Contracting Mycobacterium tuberculosis exogenously through intralesional steroid injection for keloid is an unique phenomenon not so far mentioned in literature.Primary cutaneous tuberculosis developing at keloid following intralesional steroid(ILS) which is negative for routine bacterial cultures & insensitive to routine antimicrobials warrants high index of suspicion for Mycobacterial infection. known for its varied clinical presentation, with many of them diagnosed years after the onset of symptoms. The occurrence of cutaneous nontuberculous mycobacterial (NTM) infections is being increasing reported. Although most pathogenic species of NTM may cause skin and soft tissue infections, Mycobacterium marinum, Mycobacterium ulcerans and the rapidly growing mycobacteria such as Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium abscessus are the most frequent causes.(1) However there is rarely any report of infection with Mycobacterium tuberculosis in patients of keloid following intralesional steroid injection. Cutaneous infections by NTM usually occur following contact of surgical or traumatic wounds with water or other contaminated source although cutaneous infections with Mycobacterium tuberculosis following surgical and traumatic wounds is very rare. Among the immunosuppressed it can occur as a consequence of a disseminated mycobacterial disease. A high index of suspicion about Mycobacterium tuberculosis and NTM infections is necessary, in those with chronic infections of the skin and soft tissue, to ensure prompt and appropriate treatment. (3) Abscess formation at the site of the puncture wound is most often due to rapidly growing mycobacteria. Wallace and coworkers noted that M. fortuitum and M. chelonae were the predominant isolates when they reviewed 125 cases of human infections caused by rapidly growing mycobacteria. Among these 59% had cutaneous infections following surgery, accidental trauma or needle injections. (4) We report a case of subcutaneous abscesses due to M. tuberculosis following intralesional steroid in a patient with keloid. Literature from our subcontinent suggests association of mycobacterial infection following yellow jacket sting and recurrent soft tissue infections. (5,6) However, we were unable to retrieve literature regarding association of keloids with M.tuberculosis following a PubMed search, which emphasizes the uniqueness of our report. II. Case Report A 43-year-old man who is a non diabetic and non hypertensive, presented with keloid lesions of 10- years duration. He noticed that the size increased gradually over a period of time which prompted him to consult a dermatologist, who administered intralesional steroid injection given once a month for 7 months. The patient noticed progressive increase in size of the lesion followed by drainage of pus when he was referred to our facility at Dermatology OPD of School of Tropical Medicine,Calcutta. A diagnosis of pyogenic infection in a keloid was made and he was advised oral and topical antibiotics, but there was no improvement. On examination he was afebrile and there were no palpable lymph nodes. Single keloid was observed over the manubrium, (3 × 1.5 × 1.5 cm) The lesion was associated with sinuses which was discharging pus. He had no family history of keloids. No abnormal findings were seen in his blood picture and chest X-ray. Sputum for acid-fast bacilli (AFB) and Mantoux test were negative. Serology for HIV and VDRL were non- reactive.Histopathology was not performed apprehending flaring up of keloid following punch biopsy induced trauma. Pus was aspirated from the lesions for microbiological studies. Gram stain showed plenty of pus cells but no bacteria, while Ziehl-Neelsen stain revealed plenty of acid-fast bacilli in a background of polymorphs raising the possibility of mycobacteria. Routine bacterial culture of the pus showed growth of Klebsiella pneumonia and MRSA for which he was given antibiotics according to sensitivity, but still there was no improvement. BACTEC was done which showed growth of Mycobacterium tuberculosis and line probe assay did not show any resistance to INH or Rifampicin. Following this Interferon Gamma Release Assay was done