Reasoning GP · Algorithm · 1-page summary

Itch in pregnancy

For: pregnant women with new itch, with or without a rash, at any gestation. Not for: itch outside pregnancy (use the widespread itch algorithm). Suspected ICP, pre-eclampsia and fetal concerns are managed by maternity — the GP recognises, tests and refers.

Reviewed October 2026 · next review April 2027

RCOG GTG 43RCOG GTG 13UKHSA varicella PEPBADUKMEC

Core rule: new unexplained itch in pregnancy, especially without a primary rash and worse on the palms, soles or at night, is intrahepatic cholestasis of pregnancy (ICP) until bile acids and LFTs say otherwise. ICP carries a stillbirth risk; normal LFTs or a normal CTG exclude nothing.

0Stop — call 999 now

Lip or tongue swelling, throat tightness, breathlessness (anaphylaxis) → 999. IM adrenaline first; antihistamines must not delay it.
Maternal collapse, haemodynamic instability, seizure or severe neurological symptoms (eclampsia) → 999
Jaundice with confusion, hypoglycaemia, severe vomiting, severe abdominal pain or features of acute liver failure (acute fatty liver, HELLP) → 999
Chickenpox with breathlessness or chest symptoms (varicella pneumonia) → 999. Reduced fetal movements alone → maternity triage now; 999 only if maternal collapse, severe illness or unable to transfer safely.

1Triage by pattern — rash or no rash first

Pattern	Action
No primary rash	Palms/soles, worse at night, usually third trimester → Same-day obstetric + urgent bile acids and LFTs (ICP)
Jaundice	Yellow sclerae, dark urine, pale stools → Same-day obstetric / medical
Blisters	Periumbilical urticarial plaques → tense blisters → Urgent dermatology + Same-day obstetric (pemphigoid gestationis)
Other rash	Classify (block 4); GP manages only once ICP and serious causes are excluded

2Screen — one row is enough

Reduced or changed fetal movements → Maternity triage now. Do not wait for the next antenatal appointment.
New BP ≥140/90 from 20 weeks → Same-day maternity. Severe headache, visual disturbance, epigastric pain or sudden swelling → Same-day even if BP is normal.
Persistent itch with normal initial bile acids/LFTs → Same-day obstetric repeat bloods; ICP can develop later.
Polymorphic eruption with fever, facial or mucosal involvement → Same-day
Chickenpox: significant exposure, not immune → Same-day post-exposure prophylaxis advice. New rash → Same-day obstetric; isolate from other pregnant patients.

3Assess

☐ BP; urinalysis if hypertension or pre-eclampsia concern ☐ Whole skin: primary lesion or excoriations only; periumbilical involvement or sparing ☐ Sclerae ☐ Fundal height, fetal heart, fetal movements documented ☐ Random (non-fasting) bile acids + LFTs — do not delay for fasting ☐ Medicines (co-amoxiclav, erythromycin, nitrofurantoin)

Not in primary care: CTG as reassurance; routine clotting.

4Classify — only if the screen is negative

ICP — itch without rash plus peak bile acids ≥19 µmol/L (severe ≥100) → obstetric-led care.
Polymorphic eruption (PEP) — urticarial papules in striae, spares the umbilicus, late third trimester → GP; benign.
Pemphigoid gestationis — starts periumbilically, blisters, any trimester → urgent dermatology (biopsy + immunofluorescence).
Atopic eruption — atopy, excoriated papules, dry skin, earlier than ICP, normal bile acids → GP.
Candida / scabies — vulval itch with white discharge; burrows in web spaces, contacts itchy → GP.
Uncertain — no clear local cause → bile acids + LFTs; “dry skin” only once ICP is excluded.

5Treat today — doses: NICE/SPC, BNF, local formulary

All: emollient at least 4× daily, cool baths, loose cotton clothing. Chlorphenamine 4 mg at night for sleep (weigh sedation near delivery).
ICP: ursodeoxycholic acid, vitamin K and birth timing are obstetric decisions.
PEP / atopic eruption: topical steroid of appropriate potency, smallest effective quantity. Candida: 7-day topical clotrimazole; avoid oral fluconazole. Scabies: permethrin 5%, repeat at 1 week, treat contacts together; avoid lindane.
Chickenpox: non-immune exposure → aciclovir 800 mg QDS or valaciclovir 1 g TDS, day 7–14 after exposure. Rash onset valaciclovir 1 g TDS, day 7–14. Rash <24 h atlt;24 h ago at ≥20 weeks → oral aciclovir should be prescribed.

6Refer routinely

LFTs not explained by ICP, positive hepatitis serology → hepatology.
Atopic eruption not responding to emollient + mild topical steroid; dermatosis worsening or spreading → dermatology.
After ICP: itch, bile acids, LFTs ≥4 weeks after birth. Record ICP; bile acids + LFTs at next booking; contraception per UKMEC.

7Never reassure by

Normal LFTs — bile acids are more sensitive early.
One normal result while the itch persists.
A normal CTG — it does not remove stillbirth risk.
No rash — that is the ICP pattern, not a reason to relax.
Calling it dry skin before ICP is excluded.
A normal surgery BP when pre-eclampsia symptoms are present.

8Safety-net — say it, then document it

999 “Call 999 if you collapse or have a fit, if your lips or tongue swell or your throat feels tight, if you are breathless with chickenpox, or if you are yellow with confusion, severe vomiting or severe tummy pain.” Now “If your baby's movements slow down or change, call maternity triage straight away — don't wait for your next appointment.”

Same day “Contact us or maternity today if the itch persists or worsens despite treatment or normal blood tests, your eyes go yellow or urine dark, you get a bad headache, vision problems, pain below the ribs or sudden swelling, a fast-spreading rash or fever with the rash, or chickenpox contact or rash.”

✓Safe to leave primary care only if — all five, documented

No block 0–2 row applies; fetal movements normal BP checked; no pre-eclampsia features Bile acids + LFTs sent unless a clear local cause Cause named, or uncertainty stated with review owner and date Safety-net given, including fetal movements

Summary of the full Reasoning GP itch in pregnancy algorithm, which holds the detail, examination, bile-acid bands and evidence. Sources: RCOG Green-top 43 (ICP, 2022) and 13 (chickenpox); UKHSA varicella post-exposure prophylaxis (2025); British Association of Dermatologists; Resuscitation Council UK; UKMEC. Clinical reference — follow local maternity pathways and check doses: NICE/SPC, BNF.