Differential Diagnosis for Itching in the Third Trimester
Single Most Likely Diagnosis
- Intrahepatic Cholestasis of Pregnancy (ICP): This condition is characterized by itching and elevated liver enzymes, typically presenting in the third trimester. It is the most common cause of itching during pregnancy, especially in the absence of a rash.
Other Likely Diagnoses
- Pregnancy-related Pruritus: A condition where itching occurs without any identifiable cause or rash, often resolving after delivery.
- Atopic Dermatitis (Eczema): Pre-existing eczema can worsen during pregnancy due to hormonal changes, leading to itching.
- Pemphigoid Gestationis: An autoimmune skin disorder that causes itching and blistering, typically starting around the navel and spreading to other areas.
Do Not Miss Diagnoses
- Acute Fatty Liver of Pregnancy: A rare but serious condition that can cause itching, along with other symptoms like nausea, vomiting, and abdominal pain. It requires immediate medical attention.
- Cholestasis due to Other Causes: Itching can be a symptom of cholestasis caused by other conditions such as primary biliary cirrhosis or primary sclerosing cholangitis, which are less common but critical to diagnose.
- Obstetric Cholestasis: Similar to ICP but can have more severe implications for the fetus, making prompt diagnosis crucial.
Rare Diagnoses
- Polycythemia Vera: A rare blood disorder that can cause itching due to increased histamine release, though it's uncommon to present for the first time in pregnancy.
- Hepatitis: Though not typically associated with itching as a primary symptom, certain types of hepatitis can cause pruritus and should be considered in the differential diagnosis.
- Thyroid Disorders: Both hyperthyroidism and hypothyroidism can cause itching, though they are less commonly associated with itching in pregnancy compared to other symptoms.