MYCOBACTERIAL ABSCESSES AFTER BCG VACCINATION.

Editor,

A 25‐year‐old man was referred to the dermatology department with two lesions on his upper left arm. These were intermittently discharging pus and bleeding. There was no history of trauma and he was systemically well. He had no past medical history of note and was not taking medication. He was in the army and had been posted overseas to various countries including the middle east.

He recalled receiving a BCG vaccination to his left arm in 2014 with subsequent significant local reaction which resolved with scarring.

On examination, there were two erythematous nodular lesions on the lateral aspect of his left upper arm adjacent to the BCG scar. The superior lesion measured 20 x 10mm and the inferior lesion measured 12 x 13mm. There was no palpable axillary or cervical lymphadenopathy Figure 1.

Fig 1.

 

Diagnostic punch biopsies were performed for histopathology and culture. Histopathology showed granulation tissue with two ill-defined microscopic granulomatous foci (Figure 2). MTB (Mycobacterium bovis) complex was cultured.

Fig 2.

 

Additional PCR testing performed and confirmed a BCG strain.

The BCG strain was sensitive to Isoniazid, Ethambutol, Rifampicin and resistant to Pyrazinamide.

Other investigations included: Leishmaniasis serology negative, HIV negative, ESR, U&E, LFTs, CRP and Chest x-ray normal.

He was referred to infectious diseases clinic and prescribed Rifampicin, Isoniazid, Ethambutol and Pyridoxine for 9 months. At review after 2 months of treatment, the lesions were no longer itchy and were not discharging pus or blood. On examination, the lesions were less indurated and erythematous.

The Bacille Calmette-Guérin (BCG) vaccine is a vaccine against Mycobacterium Tuberulosis infection which has been in use since 1921. BCG uses a strain of live attenuated Mycobactium Bovis.1

In the United Kingdom, the BCG vaccine was administered to all secondary school children until 2005 when a targeted programme for those at higher risk of TB was introduced.1

The BCG vaccine has been administered more than 4 billion times. Adverse events in BCG administration are rare. In a study of 117,533 vaccines abscesses were reported in 0.02% of patients2 and in another study the incidence of BCG abscess of 0.05%.3

There are no large randomised control trials investigating treatment of BCG abscesses.

A random, open, group control study of 33 patients compared isoniazid vs isoniazid/rifampicin; the combination therapy showed a higher cure rate with acceptable side effect profile.4 This was the case with our patient. There are case reports of surgical excision or observation

In summary, we report a case of BCG abscesses as a rare adverse reaction to the BCG vaccine in an immunocompetent individual. These abscesses are currently responding to treatment with anti-tuberculosis medications. This case highlights that MTB infection should be considered in patients who present cutaneous eruptions after receiving BCG vaccination.