Itch in pregnancy

Obstetrics

Antenatal clinic or obstetric triage, usually the third trimester

The first question

Is there a rash, and are the bile acids raised?

Two patients: the gestational age and the maternal stability first, then the fetal status.

01
Rash or no rash
Itch without a primary rash, worst on the palms and soles and at night, is cholestasis until the bile acids say otherwise; an itch with a rash is a dermatosis of pregnancy or an ordinary skin disease.
02
Bile acids and liver enzymes
Fasting serum bile acids and liver enzymes; repeat weekly if normal and the itch persists, because the itch can precede the rise.
03
Fetal wellbeing
Movements, and the plan of surveillance and timing of birth set by the peak bile acid level.
04
Treat the symptom
Emollients and antihistamines for the itch; ursodeoxycholic acid improves the itch in cholestasis; topical steroids for the dermatoses.
05
Postpartum
Confirm the liver tests and itch resolve after birth; persistent abnormality is another diagnosis. Counsel about recurrence and about estrogen-containing contraception.

Where it is

Each opens the structure on the 3D pelvis.

Where the itch started (palms and soles) and its timing (worse at night)
Any rash, and whether the rash came first or from scratching
Dark urine, pale stools, jaundice, right upper quadrant pain
Gestation and fetal movements
Personal or family history of cholestasis of pregnancy, gallstones or hepatitis
Medications, supplements and new products on the skin
Multiple pregnancy and assisted conception, which raise the chance of cholestasis
Skin disease before pregnancy: eczema, psoriasis, urticaria

Skin: excoriations without a primary lesion, or the morphology and distribution of a rash (umbilical sparing in the polymorphic eruption, periumbilical onset in pemphigoid gestationis)
Jaundice, hepatomegaly, right upper quadrant tenderness
Blood pressure and urine protein: itch is not part of pre-eclampsia, but liver pain can be
Symphysis-fundal height and the fetal heart

Fasting serum bile acids
Liver enzymes and bilirubin
Hepatitis serology, and a liver ultrasound if enzymes are markedly raised or pain is present
Coagulation screen when cholestasis is prolonged or severe
Fetal surveillance according to the bile acid level and unit protocol

Diagnosis	Favours	Against	Urgency
Intrahepatic cholestasis of pregnancy	Itch of palms and soles without a rash, worse at night, third trimester, raised bile acids	A primary rash, normal bile acids on repeat testing	urgent
Polymorphic eruption of pregnancy	Itchy urticarial papules and plaques starting in abdominal striae, sparing the umbilicus, first pregnancy, late third trimester	No rash, raised bile acids	routine
Pemphigoid gestationis	Urticarial plaques then tense blisters starting around the umbilicus, second or third trimester	Umbilical sparing, no blisters	urgent
Atopic eruption of pregnancy	Eczematous or papular rash on flexures and trunk, earlier in pregnancy, history of atopy	Palm and sole itch without a rash	routine
Scabies, drug reaction or another skin disease	Burrows and household itch; a new drug; a rash typical of a known condition	Itch confined to palms and soles with normal skin	routine
Viral hepatitis or another liver disease	Jaundice, malaise, markedly raised transaminases, risk factors	Isolated bile acid rise with mildly raised enzymes	urgent

Pitfalls this pathway refuses

Prescribing an antihistamine for 'pregnancy itch' without checking the bile acids
Accepting one normal bile acid result when the itch persists
Missing pemphigoid gestationis because the blisters have not appeared yet
Not planning the timing of birth by the bile acid level
Forgetting to confirm resolution after birth