Article in Japanese

A case of gangrenous papulonecrotic tuberculoid diagnosed by skin biopsy

Hayaki AKEDA^1） , Toshihide YOSHIKAWA^1） , Yumekichi MAEDA^1） , Kenta YAMADA^1） , Yusei OHSHIMA^1）

Papulonecrotic tuberculoid is a reaction of hypersensitivity to the Mycobacterium tuberculosis complex component including Bacillus Calmette-Guerin (BCG) vaccine. It is distinguished from true cutaneous tuberculosis, in which Mycobacterium tuberculosis complex is evident in the lesions. A 7-month-old boy was inoculated with BCG vaccine at 5 months of age. Koch’s phenomenon was not observed. However, 39 days after vaccination, erythematous papules were observed on the face and around the inoculation scars before gradually distributing to the extremities. Three weeks after onset of the disease, the patient was admitted to hospital due to fever and low feeding. Immunological examination showed no abnormalities. New skin lesions appeared in spite of receiving antibiotics, and so a skin biopsy was then performed. As a polymerase chain reaction test for tuberculosis on the tissue was negative, and a Ziehl-Neelsen staining test did not prove the organism, the illness was diagnosed as papulonecrotic tuberculoid. By natural course, the patient recovered from the fever and low feeding within a few days, and new skin lesions were not observed at 4 months post onset. Patients who develop cutaneous tuberculosis, due to Mycobacterium bovis BCG, may have underlying immunodeficiency, which may lead to severe disease. Therefore, timely skin biopsy is essential to distinguish it from tuberculoid rash, especially in cases with skin lesions and systemic symptoms such as concomitant fever.

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1）Department of Pediatrics, Faculty of Medical Sciences, University of Fukui

Key words	papulonecrotic tuberculoid, infant, BCG, adverse reaction, skin lesions
Received	May 25, 2022
Accepted	November 11, 2022

34 (4)：285─291,2022