Differential Diagnosis for Itchy Red Nodules in the 3rd Trimester
- Single Most Likely Diagnosis
- Polymorphic Eruption of Pregnancy (PEP): This condition is the most common dermatosis in pregnancy, often presenting in the third trimester with itchy, red nodules or papules, typically starting in the abdominal striae and spreading to other areas. Its onset and symptoms align closely with the description provided.
- Other Likely Diagnoses
- Prurigo of Pregnancy: Characterized by extremely itchy nodules that can appear anywhere on the body, prurigo of pregnancy is another common condition that could fit the symptoms described.
- Atopic Eruption of Pregnancy: This encompasses a range of eczematous conditions, including atopic dermatitis, that can flare or first appear during pregnancy, presenting with itchy, red lesions.
- Pemphigoid Gestationis: An autoimmune blistering disease that typically starts in the second or third trimester, characterized by an initial phase of urticarial plaques and intense itching, which could initially be mistaken for itchy red nodules.
- Do Not Miss Diagnoses
- Intrahepatic Cholestasis of Pregnancy (ICP): Although ICP primarily presents with intense itching without a primary rash, it's crucial to consider due to its potential for severe fetal complications. The itching can sometimes lead to excoriations or secondary skin changes that might be perceived as nodules.
- Pustular Psoriasis: A rare but serious condition that can present with widespread pustules on the skin, often accompanied by systemic symptoms. It requires prompt recognition and treatment to prevent severe outcomes.
- Rare Diagnoses
- Acute Fatty Liver of Pregnancy: While not primarily a dermatological condition, it can present with a range of non-specific symptoms including skin lesions in some cases, alongside more severe systemic manifestations.
- Cholestasis of Pregnancy due to Other Causes: Certain conditions like primary biliary cirrhosis can cause cholestasis and itching during pregnancy, though these are less common than ICP.