From the Guidelines
The diagnostic workup for a rash in pregnancy should begin with a thorough history and physical examination to identify potential causes, as rashes can range from benign pregnancy-related conditions to serious infections that may affect maternal and fetal health. Initial evaluation should include assessment of rash characteristics (distribution, morphology, timing), associated symptoms, and potential exposures. Laboratory testing should include complete blood count, liver function tests, and specific tests based on clinical suspicion such as TORCH titers (Toxoplasmosis, Other infections, Rubella, Cytomegalovirus, Herpes simplex) if a congenital infection is suspected 1. For pruritic rashes, consider bile acid levels to rule out intrahepatic cholestasis of pregnancy. Skin biopsy may be necessary for unclear presentations.
Key Considerations
- Common pregnancy-specific rashes include pruritic urticarial papules and plaques of pregnancy (PUPPP), which typically responds to topical corticosteroids (medium potency like triamcinolone 0.1% twice daily) and oral antihistamines (cetirizine 10mg daily or diphenhydramine 25-50mg every 6 hours) 1.
- Pemphigoid gestationis requires dermatology consultation and may need systemic corticosteroids, with prednisolone being the most commonly used treatment in pregnancy, as it has not shown a significant increased risk of stillbirth, preterm delivery, or congenital malformations 1.
- Any vesicular rash should prompt immediate evaluation for herpes or varicella infections, which may require antiviral therapy and have significant implications for delivery planning.
Management Principles
- Management should always balance maternal symptom relief with fetal safety, using pregnancy-safe medications at the lowest effective doses for the shortest duration necessary.
- Patch testing should be undertaken with caution in pregnancy and only when required, after informed consent is obtained, as there is no available safety data, although it is considered safe when breastfeeding 1.
From the Research
Diagnostic Framework for Rash in Pregnancy
The diagnostic workup for a rash in pregnancy involves considering both pregnancy-specific and non-pregnancy specific conditions. According to 2, pregnancy-specific dermatoses can be categorized into four main groups:
- Polymorphic eruption of pregnancy
- Pemphigoid gestationis
- Intrahepatic cholestasis of pregnancy (ICP)
- Atopic eruption of pregnancy
Key Considerations
When approaching a pruritic rash in pregnancy, it is essential to consider the potential fetal risks associated with certain conditions, such as ICP and pemphigoid gestationis, which can increase the risk of prematurity and stillbirth 2. A comprehensive literature review of each condition can help clinicians recognize, diagnose, and manage these unique conditions 3.
Clinical Presentation and Diagnosis
The clinical presentation of pregnancy dermatoses can vary, but most cases involve pruritus and skin changes. For example, polymorphic eruption of pregnancy (PUPPP) typically presents with intensely pruritic papules and urticarial plaques, usually in the third trimester or postpartum 4. In contrast, ICP begins with pruritus, and skin changes are secondary 2.
Differential Diagnosis
A detailed history and physical examination are crucial in arriving at the most likely diagnosis for any patient with a generalized skin rash 5. Clinicians should consider a range of differential diagnoses, including contact dermatitis, atopic eczema, sun-induced damage, drug eruption, and general manifestations of systemic diseases or infections 5. Additionally, atopic dermatitis (AD) is a common condition that can occur during pregnancy, with 80% of cases being new-onset presentations and 20% representing recurrences or exacerbations of preexisting disease 6.