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Health condition · Clinically reviewed

Appendicitis, the classic story, modern surgery and the antibiotics-first evidence.

The commonest surgical emergency in the abdomen. Recognised early it is a straightforward day-case operation. Missed, it perforates.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, RCS, WSES and peer-reviewed surgical trial evidence you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including laparoscopic appendicectomy and the antibiotics-first evidence (CODA and APPAC).

Key facts

Appendicitis at a glance.

The essentials, in plain English - what it is, how it presents, and how it is treated in the UK today.

  • What it is

    Acute inflammation of the vermiform appendix, usually triggered by luminal obstruction that leads to distension, ischaemia and, if untreated, perforation.

  • Lifetime risk

    Around one in seven in the UK - the commonest surgical emergency in the abdomen, most often between ages 10 and 30.

  • Classic story

    Central dull pain that shifts to the right iliac fossa over 6 to 24 hours, with anorexia, nausea and a low-grade fever.

  • Diagnosis

    Clinical assessment plus bloods (raised WCC and CRP) and targeted imaging - ultrasound in children and pregnancy, CT in most adults.

  • Standard treatment

    Emergency laparoscopic appendicectomy within 24 hours (uncomplicated) or 12 hours (complicated, perforated or gangrenous).

  • Antibiotics-first

    Reasonable for selected uncomplicated cases (no faecolith) - CODA and APPAC show around 30% recurrence within 5 years.

Why this guide matters

The pathology, in one paragraph.

Something blocks the appendix - a faecolith, lymphoid swelling, a foreign body, or rarely a tumour. Pressure rises, the wall becomes ischaemic, bacteria multiply, and, if nothing is done, the appendix perforates into the abdomen. The three points below shape everything else on this page.

  • Time matters

    Uncomplicated appendicitis becomes complicated appendicitis with delay. Aim to be assessed within hours, not days.

  • Imaging supports, not replaces

    CT and ultrasound sharpen the diagnosis, but the story and the examination still lead. A normal scan does not always exclude early disease.

  • Surgery is still the default

    Laparoscopic appendicectomy is the UK standard of care. Antibiotics-first is a reasonable alternative in a carefully selected minority.

How the diagnosis is made

From first pain to a clear plan.

The steps a UK GP, A&E team or surgeon will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    History and abdominal exam

    The classic story - periumbilical pain shifting to the right iliac fossa - plus guarding, rebound, Rovsing, psoas and obturator signs.

  2. 02

    Assessing

    Bloods and pregnancy test

    FBC (raised WCC with neutrophilia), CRP (rises after 6 hours), U&Es, LFTs and beta-hCG in women of childbearing age to exclude ectopic pregnancy.

  3. 03

    Assessing

    Urinalysis

    A dipstick and MSU to exclude a urinary tract infection or renal colic mimicking appendicitis.

  4. 04

    Confirming

    Clinical scoring

    Alvarado (score >7 supports appendicitis), AIR score and the Adult Appendicitis Score (AAS) help stratify risk and guide imaging.

  5. 05

    Confirming

    Ultrasound first-line in some

    Preferred in children, pregnant patients and thin adults - looks for a non-compressible tubular structure over 6 mm with a target sign.

  6. 06

    Confirming

    CT abdomen and pelvis

    The default in adults over 45 or where the diagnosis is uncertain - over 93% sensitive and specific. MRI is used in pregnancy where US is inconclusive.

  7. 07

    Definitive

    Laparoscopy and histology

    Diagnostic laparoscopy is the definitive test when imaging is equivocal - and treats the problem in the same operation.

Typical timeline: from A&E doors to a clear surgical plan in a matter of hours.

Symptoms

What appendicitis actually feels like.

The classic story is a dull central pain that shifts to the right and becomes sharper, alongside anorexia, nausea and a low-grade fever. Not every case follows the script.

  • Periumbilical pain first

    A dull, poorly localised central pain reflecting visceral T10 innervation - the earliest symptom in the classic story.

  • Shift to the right iliac fossa

    Over 6 to 24 hours the pain migrates to McBurney’s point as the inflamed appendix irritates the parietal peritoneum.

  • Anorexia, nausea and vomiting

    Loss of appetite is nearly universal - vomiting typically follows the pain rather than preceding it.

  • Low-grade fever

    A temperature of 37.5 to 38.5 degrees is common. A higher fever suggests perforation, abscess or an alternative diagnosis.

  • Guarding and rebound

    Localised peritonism in the right iliac fossa - voluntary or involuntary guarding with rebound tenderness on release.

  • Rovsing, psoas, obturator signs

    Pain in the RIF on palpating the left iliac fossa (Rovsing), on right hip extension (psoas), or on internal rotation of the flexed hip (obturator).

  • Atypical presentations

    Retrocaecal, pelvic or long appendices, plus pregnancy, the elderly and immunosuppressed - the picture can be quiet until it is severe.

  • Red flag - generalised peritonitis

    A rigid, silent abdomen with high fever, tachycardia and hypotension suggests perforation and sepsis. Immediate hospital care.

Treatment

How appendicitis is treated in the UK.

Emergency laparoscopic appendicectomy for most, with antibiotics-first as a considered alternative for selected uncomplicated cases, and interval surgery when a mass or abscess is present.

  • Laparoscopic appendicectomy

    The standard of care in the UK - shorter stay, less pain and lower wound infection than the open approach. Usually within 24 hours of diagnosis.

  • Open appendicectomy

    Reserved for extensive perforation, dense adhesions or where laparoscopic access is not feasible - via a Lanz or gridiron incision.

  • Preop resuscitation

    IV fluids, IV broad-spectrum antibiotics (co-amoxiclav or piperacillin-tazobactam), analgesia, an antiemetic and nil by mouth before theatre.

  • Antibiotics-first (selected)

    For uncomplicated cases with no faecolith - 5 to 7 days IV then oral. Recurrence is around 30% within 5 years (CODA and APPAC trials).

  • Percutaneous drainage

    For a well-formed appendix abscess - image-guided drainage with IV antibiotics, followed by interval appendicectomy at 6 to 12 weeks.

  • Conservative for a mass

    A palpable inflammatory mass without abscess is often treated with antibiotics and bowel rest, then interval appendicectomy after 6 to 12 weeks.

  • Complicated disease

    Perforation, gangrene or generalised peritonitis needs urgent surgery (within 12 hours), 4 to 6 weeks of antibiotics and close inpatient care.

  • Histology follow-up

    The specimen is always examined. Rare findings - carcinoid, adenocarcinoma or goblet cell tumour (<1%) - trigger oncology referral, and right hemicolectomy in some cases.

What this guide is based on

The sources behind every claim on this page.

UK national guidance, international surgical society standards and the landmark antibiotics-first trials, current at the time of last review.

Key references

Guidelines and trials we relied on.

A quiet reminder

This guide is for information, not medical advice.

If you have severe, persistent or worsening abdominal pain, do not read - go to A&E or call 999.

  • NICE CKS. Appendicitis - assessment and management.

  • Royal College of Surgeons of England. Commissioning guide: emergency general surgery (acute abdominal pain).

  • WSES Jerusalem guidelines for the diagnosis and treatment of acute appendicitis (World Society of Emergency Surgery).

  • CODA Collaborative. A randomized trial comparing antibiotics with appendectomy for appendicitis (NEJM, 2020).

  • Salminen P et al. Five-year follow-up of antibiotic therapy for uncomplicated acute appendicitis - the APPAC trial (JAMA, 2018).

Red flags

When abdominal pain needs urgent care.

Appendicitis is one of a handful of abdominal emergencies where hours matter. These are the situations where you should not wait for a routine appointment.

  • Generalised peritonitis

    A rigid, silent abdomen with high fever, tachycardia and low blood pressure suggests perforation. Call 999 or attend A&E immediately.

  • Sepsis features

    High fever, rigors, confusion, mottled skin or a very fast heart rate need same-day emergency assessment - not a GP appointment.

  • Pregnancy with abdominal pain

    Appendicitis in pregnancy carries a higher risk of perforation and fetal loss - MRI is preferred if ultrasound is inconclusive. Seek urgent obstetric review.

  • Elderly patient with vague abdominal pain

    Older adults often present atypically and later - perforation rates are higher. A low threshold for imaging and surgical review is essential.

  • Immunosuppression

    Steroids, chemotherapy or diabetes can mask signs. Trust the pain rather than a normal-looking observation chart.

  • Persistent pain after negative imaging

    A normal CT does not always exclude early appendicitis - re-examine or admit for observation if the story fits.

  • Rapidly worsening pain

    A sudden change from grumbling pain to severe, generalised pain can signal perforation - go straight to A&E.

  • Postoperative fever or worsening pain

    After appendicectomy, fever, worsening pain or wound discharge may reflect abscess, wound infection or ileus - contact the surgical team.

  • Right iliac fossa mass

    A palpable mass suggests a phlegmon or abscess. It needs imaging and a surgical plan rather than a simple day-case operation.

Recovery

Life after appendicectomy, step by step.

Four things that make the biggest difference in the days and weeks after surgery - a brisk return to normal, sensible wound care, finishing any antibiotics and keeping planned follow-up appointments.

A quiet reminder

Complications are uncommon, but treatable.

Wound infection, ileus, intra-abdominal abscess, adhesions and later hernia are all recognised, mostly manageable, and rarely dangerous when spotted early.

  1. 01 Recovery

    A brisk return to normal

    After laparoscopic appendicectomy most people go home in 24 to 48 hours and are back to light activities within a week or two.

  2. 02 Wounds

    Watch the port sites

    Keep the small incisions clean and dry, and look out for redness, swelling or discharge that could point to a wound infection.

  3. 03 Antibiotics

    Finish the course if prescribed

    If you had a complicated appendicitis or the antibiotics-first pathway, completing the full course reduces the chance of recurrence or abscess.

  4. 04 Follow-up

    Interval appendicectomy if planned

    If you were managed with an abscess or a mass, the planned operation at 6 to 12 weeks removes the appendix and reduces future recurrence.

Frequently asked

Everything we get asked about appendicitis.

Quick answers on pain patterns, surgery versus antibiotics, recovery and complications.

  • What is appendicitis?

    Acute inflammation of the appendix, most often caused by something blocking its opening - a faecolith, lymphoid swelling, a foreign body or, rarely, a tumour. Pressure builds, blood supply is cut off, and without treatment the wall can become gangrenous and perforate, leading to peritonitis or an abscess.

  • What does the pain feel like?

    It usually starts as a dull, poorly localised ache around the belly button and, over 6 to 24 hours, shifts to a sharper pain in the right lower abdomen - the right iliac fossa. Moving, coughing or the drive to hospital over speed bumps often makes it worse.

  • Do I always need surgery?

    Emergency laparoscopic appendicectomy is still the standard of care in the UK, especially for complicated disease. In carefully selected uncomplicated cases without a faecolith, an antibiotics-first approach is a reasonable option, but around 30% of people need surgery within 5 years.

  • How is appendicitis diagnosed?

    It starts with the history and examination, backed up by blood tests (a raised white cell count and CRP) and a pregnancy test in women of childbearing age. Ultrasound is used first in children and pregnancy, and CT of the abdomen and pelvis is the usual choice in adults where the diagnosis is unclear.

  • How long does recovery take?

    After a straightforward laparoscopic operation most people are home within 24 to 48 hours and back to desk work within one to two weeks. Heavy lifting and strenuous exercise usually wait around 4 to 6 weeks. Recovery is slower after a perforated or complicated appendicitis.

  • What are the risks of surgery?

    Serious complications are uncommon. The main risks are wound infection, intra-abdominal abscess, ileus (a temporary slowdown of the bowel), adhesions, incisional hernia and, very rarely, injury to nearby structures. Overall mortality for uncomplicated appendicectomy is well under 1%.

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