Mpox infection increasingly manifests with anorectal disease during the recent global outbreak. Severe ulcerative proctocolitis in solid-organ transplant recipients remains rarely described. We report a 37-year-old liver transplant recipient with well-controlled HIV infection (CD4 count 661 cells/µL [35%] and HIV RNA <20 copies/mL) presenting with severe watery diarrhea, rectal pain, disseminated vesiculopustular lesions, and inflammatory proctocolitis on imaging and endoscopy. Histopathology demonstrated ulceration and cryptitis without viral inclusions, while extensive infectious evaluation was negative. Polymerase chain reaction testing of a cutaneous lesion was positive for mpox virus. Symptoms improved with supportive care and reduction of immunosuppression. This case highlights mpox as an important diagnostic consideration in immunocompromised patients presenting with severe ulcerative proctocolitis, including patients with preserved CD4 immunity and virologically suppressed HIV infection.

Lymphogranuloma venereum (LGV) is an aggressive, sexually transmitted infection caused by specific serovars (L1-L3) of Chlamydia trachomatis. Historically considered endemic to tropical regions, LGV has re-emerged in developed nations in recent decades, predominantly affecting men who have sex with men (MSM). Its clinical spectrum is broad, ranging from asymptomatic infection to severe proctitis and proctocolitis, as well as systemic inflammatory manifestations. While buboes were once the hallmark presentation, proctitis syndrome has become the predominant clinical form in contemporary MSM populations, particularly among those engaging in anal receptive intercourse. The increasing use of pre-exposure prophylaxis (PrEP) and associated reduction in condom use have been implicated in facilitating LGV transmission in HIV-negative MSM, expanding the affected demographic beyond those living with HIV. Here, we report a case of a 31-year-old HIV-negative homosexual male patient on PrEP who presented with a two-week history of worsening abdominal pain, fever, nausea, tenesmus, and night sweats. Imaging revealed dilated fluid-filled loops of small bowel consistent with high-grade small bowel obstruction (SBO), prompting an exploratory laparotomy that was unrevealing. Postoperatively, the patient developed a muco-purulent rectal discharge, and further history revealed prior chlamydia infection and a sexual partner with inguinal lymphadenopathy. A rectal swab was positive for Chlamydia trachomatis by nucleic acid amplification test (NAAT), and LGV proctocolitis was diagnosed based on high clinical suspicion. Clinical, laboratory, and imaging features are presented in detail. The patient was started on a 21-day course of doxycycline, which led to marked clinical improvement, and his sexual partner was also treated. This case emphasizes the necessity of maintaining a high index of suspicion for LGV in MSM patients on PrEP who present with gastrointestinal symptoms mimicking SBO or inflammatory bowel disease, even in the absence of HIV infection. Prompt recognition and treatment are essential to prevent complications, including rectal strictures, bowel perforation, and unnecessary surgical interventions.

Acute anorectal and perineal emergencies encompass a wide spectrum of infectious, inflammatory, traumatic, iatrogenic, and neoplastic conditions that often present with nonspecific symptoms but may rapidly progress to significant morbidity if unrecognized. Imaging plays a central role in diagnosis, assessment of disease extent, detection of complications, and treatment planning because clinical examination frequently underestimates involvement of the complex anorectal and perineal spaces. Computed tomography (CT) is the primary imaging modality in the emergency setting owing to its rapid acquisition and ability to detect abscesses, perforation, hemorrhage, extraluminal gas, and deep pelvic extension, whereas magnetic resonance imaging (MRI) provides superior soft-tissue characterization for evaluation of fistulas, sphincteric involvement, and complex inflammatory disease. This review provides an overview of the pertinent anorectal and perineal anatomy, imaging evaluation strategies, and characteristic multimodality imaging features of common anorectal and perineal emergencies. Particular emphasis is placed on key imaging findings, including rim-enhancing abscesses and fistulous tracts, soft-tissue gas with fascial extension in necrotizing infections, bowel wall thickening and perirectal inflammatory changes in proctocolitis, and the presence of extraluminal air or fluid collections associated with rectal perforation and retained foreign bodies. The review also highlights the value of a compartment-based approach in accurately delineating disease extent and guiding clinical management.

Hematochezia presenting in the neonatal period requires a thorough exploration of life-threatening and benign pathologies, including food protein-induced allergic proctocolitis (FPIES). This non-IgE-mediated food allergy is most commonly associated with cow's milk protein (CMP). It classically presents in the first weeks to months of life, following the introduction of a cow's milk-based formula or breast milk where the maternal diet includes cow's milk. We present a rare case of extremely early onset of CMP-induced proctocolitis, in a neonate presenting at 12 h of life with hematochezia. How does a food allergy develop at such a young age? We explore the current theories explaining this phenomenon.

Background: Food protein-induced allergic proctocolitis (FPIAP) is generally considered a benign and self-limited condition; however, both its natural course and the impact of management strategies on prognosis remain controversial. Data on modifiable factors influencing tolerance acquisition are limited. Methods: We conducted a retrospective cohort study including 180 infants with cow's milk-induced FPIAP. Clinical characteristics, management strategies, and outcomes were analysed. Logistic regression was used to identify factors associated with delayed tolerance, and Kaplan-Meier and Cox regression analyses were performed to evaluate time to tolerance. Results: Tolerance was achieved in 91.2% of infants, with a median time from diagnosis to tolerance of 31.1 weeks. In multivariable logistic regression, multi-food elimination at presentation (OR, 2.58; 95% CI, 1.02-6.54; p = 0.046) and a longer interval from diagnosis to reintroduction (OR per week, 1.08; 95% CI, 1.02-1.14; p = 0.022) were independently associated with delayed tolerance. Exclusive breastfeeding was associated with lower odds of delayed tolerance in univariable analysis but not after adjustment. In unadjusted time-to-event analyses, observation-first management was associated with earlier tolerance acquisition (HR, 0.37; 95% CI, 0.22-0.62; p < 0.001), whereas multiple food allergy was associated with a lower probability of tolerance acquisition over time (HR, 0.60; 95% CI, 0.41-0.88; p = 0.009). Feeding modality also showed an unadjusted temporal association with tolerance acquisition, with exclusively breastfed infants demonstrating a more favorable pattern than formula-fed infants. Conclusions: The course of FPIAP appears to be influenced not only by clinical characteristics but also by management strategies. Delayed reintroduction and multi-food elimination were associated with later tolerance, while observation-first management was associated with earlier tolerance acquisition. These findings suggest that commonly used strategies such as prolonged elimination or delayed reintroduction may warrant reconsideration in selected infants and support a more individualized and less restrictive approach to management.

The aim of this study was to investigate liver function tests and their association with clinical characteristics in children diagnosed with non-IgE-mediated food allergy. A total of 132 children with non-IgE-mediated food allergies and 127 age- and sex-matched healthy controls were retrospectively analyzed. Patient demographics, clinical features and response to treatment were analyzed. Serum aspartate aminotransferase and alanine aminotransferase (ALT) levels were measured in both groups. The mean age of the patients was 6.0 ± 3.2 months, and symptoms appeared on average at 4.0 ± 3.4 months. At the time of symptom onset, 69 children (52.2%) were exclusively breastfed. The most common symptoms were mucous (56.8%) and bloody stools (47%). Food protein-induced proctocolitis was diagnosed in 104 patients (78.8%), food protein-induced enterocolitis syndrome in 18 (13.6%) and food protein-induced enteropathy in 10 (7.6%). Cow's milk (86.3%) and egg (34%) were the most common allergens. Mean ALT levels were significantly higher in patients (35.1 ± 30.6 U/L) than in controls (23.2 ± 8.6 U/L; P = .009), and ALT elevation was observed in 10.6% of patients versus 3.1% of controls (P = .026). Transaminase levels normalized on average within 3.9 ± 1.4 months after diet elimination. No significant differences were observed between children with elevated and normal ALT levels with respect to age, gender, diet, diagnosis or atopy. A mild elevation of liver enzyme may occur in children with non-IgE-mediated food allergies and usually disappears with elimination of the food. Clinicians should consider this association at diagnosis and delay invasive interventions until dietary intervention has been attempted.