BCG vaccination‐induced suppurative lymphadenitis: four signs to pay attention to

ABSTRACT

Suppurative lymphadenitis is one of the severe complication after BCG vaccination, but its diagnostic criteria and treatment guidelines have not yet been established. In this article, we describe a case of suppurative lymphadenitis caused by BCG vaccination and propose diagnostic criteria and treatment guidelines of the disease. The lymphadenitis was presented as skin involving mass and was completely extirpated. Pathological evaluation revealed a necrotising lymphadenitis, consistent with the diagnosis of BCG lymphadenitis. The patient was administered adjuvant medical treatment with anti‐TB medications (Isoniazid and Rifampicin) for 3 months. At 6 months follow‐up, the disease was in complete remission without complications. We recommend focus on the following four signs when diagnosing BCG lymphadenitis: (i) previous history of vaccination on the ipsilateral side of the lesion, (ii) absence of any other infection signs, (iii) absence of fever and (iv) isolated axillary or supraclavicular/cervical lymph node enlargement proven by ultrasonography or computed tomography scan. BCG vaccination‐induced suppurative lymphadenitis can easily be overlooked, but prompt, accurate diagnosis followed by appropriate surgical resection should result in complete healing as in this case.

Introduction

Since the Bacillus Calmette–Guérin (BCG) vaccine had been developed in 1921, the vaccination has been used worldwide to prevent tuberculosis (TB) 1. It is recommended to routinely vaccinate all newborns with BCG in countries with tuberculosis incidence greater than 1% 2. In South Korea, where tuberculosis incidence is relatively high, a compulsory childhood immunisation programme has been implemented, with 95–99% of children being vaccinated with BCG 3.

According to WHO recommendations, the vaccine should be intradermally injected in the deltoid area within 4 weeks of birth 4. Two strains of vaccines have been distributed domestically in South Korea since 2006: Danish strain, which is inoculated intradermally at a public health centre, and the Tokyo 172 strain, inoculated by multi‐puncture device at a private medical centre 5.

Suppurative lymphadenitis is one of the severe complications after BCG vaccination 1. BCG vaccine‐induced suppurative lymphadenitis occurs in as few as 0·1–1 per 1000 inoculated subjects 5. In countries that do not routinely administer BCG vaccination, there is little information about adverse events of BCG, such as suppurative lymphadenitis. Even in countries where BCG vaccination is routinely inoculated, physicians including the paediatricians seem to be ignorant or indifferent of this side effect.

Furthermore, the diagnostic criteria and treatment guidelines for BCG vaccine‐induced suppurative lymphadenitis have not yet been established. We hereby present a case and propose diagnostic criteria and appropriate treatment guidelines through a review of literature.

Case report

A 5‐month‐old boy with no underlying medical conditions had visited a local paediatric clinic for left axillary mass (Figure 1). The mass was protruding towards the erythematous skin with no definite infection signs being observed. The patient had been vaccinated with BCG Danish strain intradermally at 3 weeks of age. The mass was first detected at 5 months of age by the parent and was observed as a 1·5 cm‐sized solid mass on ultrasonography. The local clinic diagnosed it as lymphadenitis and planned on observation.

Figure 1.

A 5‐month‐old boy who had no history of other diseases presented with a left axillary mass. The mass was protruding through the skin, and erythema was observed, but there is no another infection sign.

With no improvement, the patient visited the paediatric department of our hospital at 7 months of age. Ultrasonography revealed a 2 × 2 cm‐sized low echoic lesion with thin surrounding capsule, suspicious of suppurative lymphadenitis (Figure 2). The paediatrician diagnosed the patient having as BCG‐induced suppurative lymphadenitis and started with conservative medical treatment. Despite the medication (isoniazid for 4 months), the mass grew gradually for several months.

Figure 2.

At 7 months of age, a 2 × 2 cm lower echoic lesion with a thin wall suspected of suppurative lymphadenitis was confirmed by sonography at our paediatric clinic.

The patient was referred to plastic and reconstructive surgery department at 13 months of age for surgical intervention. Physical examination revealed a huge mass completely involving the overlying skin. CT scan showed a 5 × 4 cm‐sized necrotic cystic lesion in the left axillary region, suggestive of suppurative lymphadenitis (Figure 3). Surgical excision was planned for total extirpation of the mass.

Figure 3.

The CT scan performed at the age of 13 months showed a 5 × 4 cm‐sized necrotic cystic lesion consistent with suppurative lymphadenitis at the left axilla. There was a significant increase in size compared with sonography findings 6 months before.

During the excision intraoperatively, profuse amount of pus gushing out from the cyst was observed (Figure 4A). The abscess was totally extirpated along with its surrounding capsule (Figure 4B). Pathological evaluation revealed a necrotising lymphadenitis consistent with the diagnosis of BCG lymphadenitis. The patient received adjuvant medical treatment with anti‐TB medications (Isoniazid and Rifampicin) for 3 months. At 6 months of follow‐up, the disease was in complete remission without complications.

Figure 4.

(A) During excision, pus gushed out from the sac. (B) The abscess was extirpated, including the wall.

Discussion

BCG vaccination can result in various complications. Early complications include relatively simple ones, such as erythema, induration, ulceration, abscess and fistula, as well as severe complications, such as osteomyelitis, lymphadenitis, prolonged ulceration of injection site and disseminated BCG infection 6, 7.

Although suppurative lymphadenitis is most common among the severe complications, physicians have difficulty in making an accurate diagnosis because of their lack of knowledge and experience, and even if diagnosed, proper treatment is difficult to be performed promptly. The major problem regarding the BCG vaccination‐induced suppurative lymphadenitis is that there are no definite diagnostic criteria and treatment guidelines proposed so far 8.

Combining several review articles 8, 9, 10, 11, the following diagnostic criteria of BCG lymphadenitis can be obtained: (i) previous history of vaccination on the ipsilateral side of the lesion; (ii) absence of any other infection signs, such as tenderness or local heat on overlying skin; (iii) absence of fever and (iv) isolated axillary or supraclavicular/cervical lymph node enlargement proven by ultrasonography or computed tomography scan. BCG vaccination‐induced lymphadenitis can be diagnosed if all four of the above diagnostic criteria are satisfied.

There are no established treatment guidelines for BCG vaccine‐induced suppurative lymphadenitis. Some papers recommend conservative care, such as medication and needle aspiration, while opposing active surgical treatment 12, 13. However, there are many reports showing good results after surgical extirpation 8, 14, 15, 16.

Controversies regarding the medical treatment also exist. Several previous articles have reported that medical treatment is ineffective in suppurative lymphadenitis with fluctuations accompanied 16, 17, 18. In our case, the patient was treated medically for 4 months after initial diagnosis, but size of the abscess increased without improvement.

The advantages of early surgical treatment are rapid healing, low recurrence rate and reduced hospital stay. Simple incision and drainage should be avoided because of the likelihood of persistent draining of the wound. Surgical extirpation appears to be the treatment of choice for complete remission 13.

In conclusion, although BCG vaccination‐induced suppurative lymphadenitis can easily be overlooked, early, accurate diagnosis followed by appropriate surgical extirpation can result in complete healing.