What is the recommended treatment for a typical adult with mild‑to‑moderate rectal inflammation presenting with pain, urgency, tenesmus, and occasional bleeding, without signs of systemic infection or severe colitis?

Treatment of Rectal Inflammation (Proctitis)

For mild-to-moderate ulcerative proctitis presenting with pain, urgency, tenesmus, and bleeding, initiate combination therapy with topical mesalazine 1g daily (as suppository) PLUS oral mesalazine 2-4g daily as first-line treatment. 1, 2

First-Line Therapy

Combination topical and oral therapy is superior to either agent alone and should be the standard approach:

• Topical mesalazine 1g daily delivered as suppository (for disease limited to rectum) or foam/enema (if extending into sigmoid) 1
• PLUS oral mesalazine 2-4g daily (or balsalazide 6.75g daily, or olsalazine 1.5-3g daily) 1, 2
• Once-daily dosing of topical mesalazine is as effective as multiple daily doses and improves adherence 2
• This combination achieves remission rates significantly higher than monotherapy 1

Critical implementation point: Topical mesalazine acts more rapidly and effectively than oral aminosalicylates alone or topical steroids for inducing remission in ulcerative proctitis 3

Second-Line Therapy (If Intolerant to Topical Mesalazine)

If the patient cannot tolerate topical mesalazine:

• Switch to topical corticosteroids (budesonide 2-4mg suppository, budesonide foam, or hydrocortisone enema) 1
• Topical corticosteroids are less effective than topical mesalazine but remain superior to placebo (RR=2.83 for remission vs placebo) 1
• Continue oral mesalazine 2-4g daily alongside topical steroid 1

Escalation for Inadequate Response

If symptoms persist after 2-4 weeks on combination topical + oral mesalazine:

• Add oral prednisolone 40mg daily 1, 2
• Taper gradually over 8 weeks according to clinical response 1
• Continue topical agents as adjunctive therapy during steroid course 1
• More rapid steroid reduction is associated with early relapse 1

Critical Diagnostic Considerations Before Treatment

Before initiating therapy, exclude infectious causes:

• Test for sexually transmitted infections (Neisseria gonorrhoeae, Chlamydia trachomatis, herpes simplex virus, syphilis) particularly in sexually active patients or men who have sex with men 1, 4, 5
• Consider HIV testing in appropriate clinical contexts 4
• Rule out other infections: lymphogranuloma venereum, Giardia, amoebiasis 1
• Exclude non-infectious causes: solitary rectal ulcer, chemical colitis, radiation proctitis 1

However, treatment should not be delayed while awaiting stool microbiology results if clinical presentation strongly suggests ulcerative proctitis 1

Common Pitfalls to Avoid

Do not switch between different oral 5-ASA formulations if initial therapy fails—this is ineffective 2

Do not use topical corticosteroids as first-line therapy—they are less effective than topical mesalazine 1

Address proximal constipation with stool bulking agents or laxatives, as this can worsen rectal symptoms 1

Do not use corticosteroids for long-term maintenance—they are ineffective and carry significant toxicity 2, 6

Refractory Disease Management

For severe or refractory proctitis not responding to the above:

• Consider biologics (infliximab, vedolizumab, ustekinumab), small molecule therapy (JAK inhibitors), or topical tacrolimus 1, 2
• Obtain endoscopic re-evaluation to rule out proximal disease extension or alternative diagnoses 1
• Surgical consultation if medical therapy fails completely 2

Maintenance Therapy

Once remission is achieved:

• Continue topical mesalazine (alternate or every third night dosing may be acceptable for some patients, though daily is preferred) 1
• Continue oral mesalazine 2-4g daily indefinitely to reduce relapse risk and potentially reduce colorectal cancer risk 1, 2, 6
• Many patients with proctitis who rapidly respond may prefer on-demand treatment when symptoms recur rather than continuous maintenance 1