Episodic Face Swelling + Whole-Body Pruritus (Recurrent Every 3-4 Months, Steroid-Responsive)

Key Diagnostic Framework

1. Histamine-mediated (urticarial type) - pruritus IS a prominent feature; responds to steroids and antihistamines
2. Bradykinin-mediated (HAE / ACE inhibitor-induced) - pruritus is ABSENT; pain predominates; does NOT respond to steroids

Differential Diagnosis

1. Chronic Spontaneous Urticaria (CSU) with Angioedema - Most Likely

• Recurrent episodes of pruritic wheals + angioedema (commonly periorbital, perioral)
• Episodes resolve spontaneously; steroid-responsive
• Majority of chronic cases are autoimmune (up to 45%): autoantibodies to IgE or FcεRI alpha-chain
• Associated with Hashimoto's thyroiditis (anti-thyroid peroxidase/thyroglobulin antibodies)
• Triggers: stress, NSAID use, occult infection, food additives
• Harrison's Principles of Internal Medicine, p. 2851

2. Gleich Syndrome (Episodic Angioedema with Eosinophilia) - Key Differential

• Episodic facial edema / angioedema with fever, weight gain, and marked eosinophilia
• Elevated IL-5 during attacks; elevated eosinophil major basic protein
• No underlying malignancy in most cases
• Responds well to systemic corticosteroids; also treated with antihistamines, IVIG, or imatinib
• Andrews' Diseases of the Skin, p. 179

3. Chronic Autoimmune Urticaria

• Autoantibodies against IgE or FcεRI trigger mast cell degranulation
• Can flare episodically, especially triggered by stress, infections, or hormonal changes
• Steroid-responsive; anti-thyroid antibodies may coexist

4. Acquired C1-Esterase Inhibitor Deficiency (Acquired HAE / Acquired Angioedema Type II)

• Unlike hereditary HAE (which lacks pruritus and doesn't respond to steroids), acquired forms may have partial steroid response
• Associated with B-cell lymphoproliferative disease or autoantibodies against C1-EI
• Check C4, C1q, and C1-EI levels and function
• Andrews' Diseases of the Skin, p. 179

5. Schnitzler Syndrome

• Recurrent urticaria-like eruptions (chronic, non-pruritic wheals OR pruritic) + monoclonal IgM (rarely IgG) gammopathy
• Systemic symptoms: fever, bone and muscle pain
• Responds partially to steroids; better treated with IL-1 antagonists (anakinra)
• Fitzpatrick's Dermatology; Harrison's, p. 2851

6. CIAS1-Associated Periodic Fever Syndromes (Autoinflammatory)

• Familial Cold Autoinflammatory Syndrome (FCAS) and Muckle-Wells syndrome
• Urticaria-like rash, fever, joint pain recurring episodically
• Caused by NLRP3 (cryopyrin) mutations
• Harrison's Principles, p. 2851

7. ACE Inhibitor-Induced Angioedema (if on ACEi)

• Can occur months-to-years after starting the drug
• Usually lacks pruritus (bradykinin-mediated), but worth excluding
• 5x higher risk in Black patients; lisinopril and enalapril more common than captopril
• Andrews' Dermatology, p. 144

8. Food or Drug Allergy with Delayed/Periodic Re-exposure

• IgE-mediated: re-exposure to a concealed allergen (e.g., shellfish, peanuts, certain drugs, food additives) every few months
• Typical pattern: pruritus + urticaria + angioedema; steroid-responsive

9. Urticarial Vasculitis

• Persistent wheals (>24 h), may cause hyperpigmentation
• Associated with hypocomplementemia, SLE, Sjogren's
• Skin biopsy confirms leukocytoclastic vasculitis

10. Mastocytosis (Systemic)

• Recurrent urticaria, pruritus, flushing, angioedema triggered by alcohol, NSAIDs, opioids
• Elevated serum tryptase; skin biopsy (Darier's sign); bone marrow biopsy if systemic

Investigations to Order

Why Steroids Work

Bottom Line

1. Chronic spontaneous/autoimmune urticaria with angioedema (most common)
2. Gleich syndrome (episodic angioedema + eosinophilia) - especially if eosinophilia is found
3. Schnitzler syndrome - if fever/bone pain accompanies episodes
4. Recurring allergen exposure - if pattern correlates with seasonal or dietary changes

Clinical Analysis: Female with Abdominal Pain + Fever + Diarrhea + Throat Pain - Partial Response to Ofloxacin/Ornidazole/Loperamide

What Happened with the Treatment So Far

Most Likely Diagnoses to Consider

1. Enteric Fever (Typhoid / Paratyphoid) - HIGH PRIORITY

• Classic triad: fever + abdominal pain + diarrhea (early) that evolves into constipation
• Ofloxacin (a fluoroquinolone) was the traditional treatment, but fluoroquinolone-resistant S. Typhi is now extremely common on the Indian subcontinent
• Harrison's (2025): "Because of the high prevalence of strains of S. Typhi and S. Paratyphi with decreased susceptibility to ciprofloxacin on the Indian subcontinent, fluoroquinolones should no longer be used for empirical treatment of enteric fever in these regions."
• This directly explains why ofloxacin failed - the organism may be DSC (decreased susceptibility to ciprofloxacin, MIC ≥0.125)
• Throat pain / pharyngitis can occur as a systemic feature
• Action needed: Blood culture + Widal/Typhidot + CBC (relative bradycardia, leukopenia)
• Correct treatment: Ceftriaxone 2g/day IV x 10-14 days OR Azithromycin 1g/day PO x 5-10 days

2. Pelvic Inflammatory Disease (PID) - HIGH PRIORITY in a female

• Female patients with lower abdominal pain + fever that persists after GI treatment must be screened for PID
• Spectrum: endometritis, salpingitis, tubo-ovarian abscess, pelvic peritonitis
• Ofloxacin alone partially covers PID organisms (covers Chlamydia and Gonorrhea) but ornidazole added anaerobic cover - however PID requires a full course with adequate duration
• If not properly diagnosed as PID upfront, the regimen duration may be insufficient
• Ask: Menstrual history, vaginal discharge, cervical motion tenderness, dyspareunia
• Workup: Pelvic exam, TVS (for TOA), endocervical swab, urine pregnancy test, ESR/CRP

3. Amoebic Liver Abscess / Complicated Amoebiasis

• Ornidazole was appropriate for Entamoeba histolytica diarrhea, and diarrhea resolved
• However, if amoebic infection reached the liver (via portal circulation) before treatment, a liver abscess can develop even after diarrhea resolves
• Features: right upper quadrant or epigastric pain, fever, hepatomegaly, elevated ALP
• Workup: Liver USG urgently, serum amoebic antibodies (IFAT/ELISA)
• Management: Metronidazole 750mg TDS x 10 days + luminal agent (diloxanide furoate)

4. Typhoid Carrier with Biliary Involvement or Complication

• Chronic S. Typhi carriage more common in women (especially with biliary disease)
• Complications like intestinal perforation or hepatitis can present with persistent abdominal pain + fever
• Rose spots (faint salmon-colored macules on trunk) may be present but easy to miss

5. Appendicitis Masquerading as Gastroenteritis

• Early appendicitis can mimic gastroenteritis with diarrhea, periumbilical pain, low fever
• After loperamide stops diarrhea and antibiotics give partial coverage, an evolving appendicitis is unmasked
• Must examine: RIF tenderness, Rovsing's sign, Psoas sign
• Workup: USG abdomen, CBC (rising neutrophilia)

6. Urinary Tract Infection / Pyelonephritis

• Upper UTI in females: flank/loin pain (can mimic abdominal pain), fever, dysuria, body aches
• Throat pain in context of systemic sepsis is possible
• Workup: Urine R/E + culture, urine pregnancy test

7. Drug-Related Causes

• Ofloxacin/ornidazole-induced pancreatitis - there are documented case reports of this drug combination causing acute pancreatitis (elevated lipase/amylase, epigastric pain, fever)
• C. difficile colitis - ofloxacin can precipitate this; diarrhea may recur but initially stops with loperamide
• Throat pain: ofloxacin is listed as a cause of pharyngitis/throat irritation

Immediate Investigation Priority

Antibiotic Reassessment

• Enteric fever on the Indian subcontinent (fluoroquinolone resistance)
• PID (needs full course with metronidazole + doxycycline +/- ceftriaxone)

• Suspected typhoid (Indian subcontinent): Switch to Ceftriaxone 2g IV OD or Azithromycin 500mg-1g OD x 7-10 days
• Suspected PID: Ceftriaxone 500mg IM single dose + Doxycycline 100mg BD x 14 days + Metronidazole 400mg TDS x 14 days
• Suspected amoebic liver abscess: Metronidazole 750mg TDS x 10 days (not ornidazole, which has less evidence for abscess)

Throat Pain - Why Is It There?

• Systemic viral co-infection (e.g., influenza or EBV with gastroenteritis features)
• Typhoid occasionally causes pharyngitis as a systemic manifestation
• Ofloxacin side effect (dryness, pharyngitis listed in SPC)
• Streptococcal pharyngitis concurrent with GI illness
• Consider: Throat swab for culture, monospot test if EBV suspected

Summary: What to Do Now

1. Do NOT give loperamide again - it masks the picture and is contraindicated if invasive infection (Salmonella, Shigella) is the cause
2. Admit for workup if fever is high-grade (>39°C) or patient looks toxic
3. Blood culture + CBC + LFT + lipase + urine culture + USG abdomen/pelvis + urine pregnancy test
4. Pelvic examination is mandatory in any female with lower abdominal pain + fever
5. Escalate antibiotics - ofloxacin is insufficient for typhoid in endemic regions and needs reassessment for PID coverage
6. Watch for red flags: RUQ tenderness (liver abscess), RIF guarding (appendicitis), rebound tenderness (perforation), hypotension (sepsis)

Metronidazole 400 BD + Azithromycin 500 BD - Is This a Good Regimen Here?

Breaking It Down by the Likely Diagnoses

For Enteric Fever (Typhoid) - Azithromycin 500 BD ✅ (but dose needs adjustment)

• Standard dosing from Harrison's 2025: Azithromycin 1g/day OD x 5-7 days for uncomplicated typhoid
• Your proposed 500mg BD = 1g total/day - this is the same total daily dose, so it's acceptable
• However, azithromycin is conventionally given once daily (OD), not twice daily, because its long half-life (~68 hours) and tissue concentration make OD dosing more appropriate
• Recommended: Azithromycin 500mg OD x 7-10 days (or 1g OD x 5 days) is preferred over BD dosing

For PID - Metronidazole 400-500 BD ✅ + Azithromycin ⚠️ (incomplete)

• Standard outpatient PID regimen: Ceftriaxone 500mg IM single dose + Doxycycline 100mg BD x 14 days ± Metronidazole 500mg BD x 14 days
• Metronidazole 400-500 BD x 14 days covers anaerobes well ✅
• Azithromycin alone does NOT adequately cover PID - it covers Chlamydia but misses Gonorrhea (which needs a cephalosporin), and the duration is insufficient
• Azithromycin 1g single dose + metronidazole is an alternative, not the preferred, PID regimen - and still needs anaerobic/gonococcal cover
• Without a cephalosporin (ceftriaxone), gonococcal PID will not be adequately treated

For Amoebic Infection (if diarrhea was amoebic colitis or liver abscess) - Metronidazole ✅

• Metronidazole 400-800mg TDS x 7-10 days is the treatment for invasive amoebiasis
• 400mg BD is underdosed for amoebic disease - standard dose is 400-800mg three times daily (TDS) not twice daily (BD)
• Azithromycin has no role here

Summary Table

What Would Be Better

• Azithromycin 500mg OD x 7-10 days (or 1g OD x 5 days)
• Metronidazole is not needed unless there is concurrent amoebic infection
• If patient is sick or vomiting: switch to Ceftriaxone 2g IV OD x 10-14 days

• Add Ceftriaxone 500mg IM single dose (one shot)
• Then: Doxycycline 100mg BD x 14 days + Metronidazole 400-500mg BD x 14 days
• Azithromycin can replace doxycycline if doxycycline is not tolerated: 1g stat, then 500mg OD x 6 days

• Ceftriaxone 500mg IM stat (single shot, covers both typhoid AND gonorrhea)
• • Azithromycin 500mg OD x 7 days (covers typhoid + Chlamydia)
• • Metronidazole 400mg TDS x 7-10 days (covers anaerobes + possible amoebiasis)

One Key Caution

Assessment: Metronidazole 400mg TDS + Azithromycin 500mg OD

✅ Why This Works Well Here

• Covers intestinal anaerobes, residual protozoal infection (Giardia, Entamoeba)
• Covers anaerobic component of PID
• Addresses any persistent gut infection that ornidazole may have incompletely treated
• Standard dose for invasive GI amoebiasis and mixed anaerobic infection

• Covers enteric fever (typhoid) - appropriate empirical choice given fluoroquinolone failure
• Covers Chlamydia trachomatis if PID is a component
• Covers atypical organisms (Mycoplasma, which can cause pharyngitis + systemic illness - explaining the throat pain)
• Long tissue half-life means OD dosing is pharmacokinetically correct

What Each Symptom Is Being Covered By

Gap That Remains

• If the patient has cervical motion tenderness, vaginal discharge, or is sexually active - one shot of Ceftriaxone 500mg IM would complete the PID coverage
• This is a single injection, not a blood test - may be more acceptable to the patient
• If she categorically refuses all injections and PID features are absent or low probability, your two-drug oral regimen is a reasonable empirical choice

Duration

Safety Check

• Metronidazole + Azithromycin together: no major interaction, safe combination
• Both can cause mild nausea - advise taking after food
• Metronidazole: strict no alcohol during course
• QT prolongation risk with azithromycin is low in an otherwise healthy young female, especially since ofloxacin has likely been stopped

Follow-Up Instruction (Mandatory)

• If fever does not defervesce within 48-72 hours - she must reconsider blood tests or hospital referral
• Red flag symptoms to return immediately: severe RUQ pain (liver abscess), rigid abdomen (perforation), breathlessness, confusion, inability to take orals
• Rising fever on day 3-4 despite this regimen = do not wait further - escalation to ceftriaxone IV is needed