Management of Complex Anal Fistula in Recurrent Perianal Abscess: A Case Report

BACKGROUND Perianal abscesses are acute suppurative infections in perianal soft tissues or spaces, frequently associated with Crohn's disease, malignancies, diabetes, immunosuppression, or prior anorectal procedures. Persistent or recurrent infections following incision and drainage (I&D) with standard wound care may indicate occult anal fistulas, necessitating thorough evaluation. CASE REPORT A 32-year-old woman presented with acute right buttock/thigh swelling, pain, and hypotension, initially diagnosed as septic shock. No predisposing factors were identified. Initial management included antibiotics and CT-guided drainage, resolving symptoms temporarily. One month later, she developed recurrent fever, chills, and a subcutaneous abscess. Repeated evaluations revealed no fistula; I&D with vacuum sealing drainage (VSD) and plastic surgery-led wound closure achieved transient improvement. Three months postoperatively, purulent discharge recurred. Persistent symptoms prompted referral to a colorectal hospital. Rectal MRI identified a high complex-type anal fistula, confirmed surgically. Definitive fistula repair led to complete resolution. CONCLUSIONS Recurrent perianal infections, particularly in diabetics or obese patients, require vigilance for occult fistulas. This case highlights the bidirectional relationship between abscesses and fistulas, emphasizing that negative initial evaluations do not exclude fistula formation. MRI demonstrates superior diagnostic accuracy for complex fistulas and should be prioritized in refractory cases. Repeated drainage without addressing underlying fistulous tracts lacks long-term effectiveness. Early multidisciplinary collaboration and definitive surgical intervention are critical for sustained recovery. Specialized imaging and timely referrals optimize outcomes in diagnostically challenging scenarios.