05 June 2026
: Case report 
Rare Complications in Crohn’s Disease: Diagnostic and Therapeutic Challenge of Dermal Abscesses Caused by Nontuberculous Mycobacteria Following Infliximab Therapy, and Fluoroquinolone-Related Achilles Tendon Rupture
Unusual clinical course, Challenging differential diagnosis, Unusual or unexpected effect of treatment, Diagnostic / therapeutic accidents, Rare disease, Adverse events of drug therapy, Educational Purpose (only if useful for a systematic review or synthesis)
Nidhi Gupta ABCDEF 1*, Kriti Yadav BF 1, Andrew Carter CD 1, Brandon Karimian
DF 1, Charly Almonte EF 1, Rahul Sampath ABCDG 1
DOI: 10.12659/AJCR.952790
Am J Case Rep 2026; 27:e952790
Table 2 Microbiology, immunology, and imaging workup results.
| Investigation | Results |
|---|---|
| Rapid influenza A and B/COVID/RSV | Negative |
| Superficial swab aerobic/anaerobic cultures | No growth at 5 days |
| urine Ag | Negative |
| Urine chlamydia and gonorrhea | Negative |
| Syphilis screen-RPR | Non-reactive |
| HIV Ag/Ab | Non-reactive |
| Blood cultures × 2 | Sterile at 5 days |
| ANA | Negative |
| ANCA (MPO, PR-3) | Negative (1.3, 1.2) |
| RA factor | <3.5 |
| Hepatitis C antibody | Non-reactive |
| HBsAg | Non-reactive |
| Surgical pathology (right knee lesion) | Acutely inflamed benign skin with granulation tissue and necrosis |
| Biopsy specimen stains for fungal and AFB | Negative for fungal organisms and acid-fast bacilli |
| Aerobic culture | – susceptible to cefipime, ceftazidime, gentamicin, ciprofloxacin, levofloxacin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole |
| Fungal culture | Negative |
| AFB culture | |
| AFB susceptibility rapid-grower | Susceptible to cefoxitin, imipenem, moxifloxacin, clarithromycin, amikacin, TMP/SMX, linezolid. Intermediate sensitivity to ciprofloxacin. Resistant to tobramycin, doxycycline |
| Chest X-ray | Normal |
| CT lung cancer screening | Multiple pulmonary nodules |
| CT lower extremity | Superficial ulcer/laceration of the subcutaneous soft tissue of the posterior medial proximal left leg. No evidence of underlying abscess or organized fluid collection |
| CT abdomen pelvis | No abscess or fistula seen |
| Venous doppler | No evidence of deep vein thrombosis |
| 2D echocardiography | Echogenicity noted on the non-coronary cusp-pulmonary valve, likely focal calcification vs vegetation vs mass |
| Transesophageal echocardiogram | Normal, no vegetation/mass/thrombus |
| COVID – corona virus disease; RSV – respiratory syncytial virus; Ag – antigen; Ab – antibody; RPR – rapid plasma reagent; ANA – anti-nuclear antibody; ANCA – anti neutrophil cytoplasmic antibody; MPO – myeloperoxidase; PR-3 – proteinase 3; RA factor – rheumatoid arthritis factor; HBsAg – hepatitis B surface antigen; AFB – acid-fast bacilli; TMP/SMX – Trimethoprim/sulfamethoxazole; CT – computed tomography. | |