Differential Diagnosis for Itchy Nodules at 30 Weeks Pregnancy
Single Most Likely Diagnosis
- Polymorphic Eruption of Pregnancy (PEP): This condition is the most common dermatosis in pregnancy, occurring in approximately 1 in 160 pregnancies. It typically presents with itchy, urticarial papules and plaques, often starting in the abdominal striae and spreading to other areas. The onset is usually in the third trimester, making it a prime candidate for the symptoms described.
Other Likely Diagnoses
- Prurigo of Pregnancy: Characterized by itchy nodules, this condition can appear similar to PEP but tends to have a more chronic course. It's less common than PEP but still a consideration in pregnant women with itchy skin lesions.
- Atopic Eruption of Pregnancy: This encompasses a range of eczematous conditions, including atopic dermatitis, that can flare or first appear during pregnancy. It's a likely diagnosis given the itchy nature of the nodules.
- Pemphigoid Gestationis: An autoimmune blistering disease that typically starts during the second or third trimester, characterized by itchy urticarial plaques that can evolve into blisters. Although less common, its autoimmune nature and potential for blister formation make it a notable consideration.
Do Not Miss Diagnoses
- Cholestasis of Pregnancy: While primarily known for causing intense pruritus without a primary rash, in rare cases, it can lead to secondary skin changes due to scratching. Missing this diagnosis could lead to significant morbidity for both mother and fetus due to its association with premature birth and stillbirth.
- Intrahepatic Cholestasis of Pregnancy (ICP): Similar to cholestasis, ICP can cause intense itching, sometimes leading to skin excoriations or nodules from scratching. It's crucial to diagnose ICP due to its implications for fetal health and the need for close monitoring.
Rare Diagnoses
- Pruritic Folliculitis of Pregnancy: A rare condition characterized by itchy, follicular papules, typically on the arms, legs, and buttocks. It's a diagnosis of exclusion and less commonly encountered.
- Pruritic Urticarial Papules and Plaques of Pregnancy (PUPPP): Although PUPPP is the most common dermatosis in pregnancy, the term "rare" here is relative, considering the context of other less common conditions. However, it's essential to differentiate PUPPP from other conditions due to its distinct presentation and implications for management.