Acute proctitis refers to inflammation of the rectal mucosa, typically presenting with rectal pain, tenesmus, urgency, and bleeding. It reflects disruption of the mucosal barrier with activation of innate and adaptive immune pathways, leading to oedema, ulceration, and increased vascular permeability. In UK practice, early recognition is important because causes range from reversible infection to chronic inflammatory bowel disease. Management is most effective when directed at the underlying aetiology rather than symptom control alone.

📌 Causes of Acute Proctitis

🦠 Infective
- Sexually transmitted infections: gonorrhoea, chlamydia (including LGV), HSV, syphilis
- Enteric pathogens: Campylobacter, Shigella, Salmonella
- Clostridioides difficile (post-antibiotics)
🔥 Inflammatory
- Ulcerative colitis (ulcerative proctitis)
- Crohn’s disease with rectal involvement
☢️ Radiation-induced
- Following pelvic radiotherapy (prostate, cervical, rectal cancer)
💊 Drug / Chemical
- NSAIDs, suppositories, enemas, chemical irritants
⚠️ Other
- Ischaemia, trauma, rectal foreign bodies
- Solitary rectal ulcer syndrome

🧠 Pathophysiology

Most forms of acute proctitis involve epithelial injury followed by immune activation within the lamina propria. In infective disease, pathogen invasion triggers neutrophilic inflammation and mucosal ulceration. In inflammatory bowel disease, dysregulated T-cell responses and cytokine release (TNF-α, IL-13) perpetuate chronic mucosal damage. Radiation causes endothelial injury and fibrosis, leading to ischaemia and impaired mucosal healing.

🔍 Clinical Features

Rectal pain and burning sensation
Tenesmus and urgency
Rectal bleeding or mucus discharge
Diarrhoea (may be minimal in isolated proctitis)
Systemic features in infection or severe inflammation

🧪 Investigation

Stool culture and C. difficile toxin if diarrhoea present
Rectal swabs for STI screening in at-risk patients
Blood tests: FBC, CRP, ESR
Flexible sigmoidoscopy with biopsy if persistent or severe
Consider HIV testing where appropriate

💊 Management and Treatment

Infective
- Targeted antibiotics/antivirals based on microbiology
- Empirical STI treatment if high clinical suspicion
Inflammatory (IBD-related)
- Topical mesalazine suppositories first-line
- Topical steroids if refractory
- Escalation to oral/systemic therapy if extensive disease
Radiation
- Sucralfate enemas, topical steroids
- Referral for endoscopic therapy if bleeding persists
Supportive
- Analgesia, stool softeners, hydration
- Avoid rectal irritants

🚨 Red Flags (Urgent Referral)

Severe bleeding or haemodynamic compromise
Systemic sepsis
Suspected malignancy
Failure to respond to initial therapy

📚 Key Learning Points

Acute proctitis is a symptom-driven diagnosis that requires systematic exclusion of infection before assuming inflammatory disease. Topical therapy is highly effective because it delivers high drug concentrations directly to the affected mucosa. In UK practice, early STI screening and gastroenterology referral for persistent symptoms are essential to prevent chronic morbidity. Thinking mechanistically—epithelial injury, immune activation, and vascular compromise—helps guide rational treatment.

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Active Proctitis