RESUMO
Although scrofuloderma is the most common subtype of cutaneous tuberculosis, its diagnosis is often delayed. In this case, ciprofloxacin was first administered as only Pseudomonas aeruginosa was detected by initial culture tests. Mycobacterium tuberculosis is usually susceptible to quinolone antibiotics, hence the partial improvement in inflammatory symptoms and subsequent delay in diagnosis. Our case serves as a reminder that we should always be aware of the possibility of cutaneous tuberculosis being the cause of an abscess, especially when the abscess is not completely resolved by antibiotics. Moreover, our case reminds us that it is necessary to conduct repeated culture tests, rather than relying purely on polymerase chain reaction (PCR) results, given that cases of PCR-negative acid-fast bacilli (AFB) culture-positive scrofuloderma have been reported. Fine needle aspiration is a less invasive and useful way to collect culture samples.