What is the treatment for an allergy to pregnancy, also known as polymorphic eruption of pregnancy (PEP) or atopic eruption of pregnancy?

Treatment of Polymorphic Eruption of Pregnancy (PEP)

Topical corticosteroids of low to medium potency combined with emollients are the first-line treatment for polymorphic eruption of pregnancy (PEP), with oral prednisolone reserved for severe cases that don't respond to topical therapy.

Understanding Polymorphic Eruption of Pregnancy

Polymorphic eruption of pregnancy (PEP), also known as pruritic urticarial papules and plaques of pregnancy (PUPPP) or atopic eruption of pregnancy, is one of the most common pregnancy-specific dermatoses. It typically presents with the following characteristics:

• Most common in primigravidae (70% of cases) 1
• Usually occurs in the third trimester (mean onset at 34 weeks) 1
• Higher incidence in multiple gestations (13% of cases) 1
• Characterized initially by pruritic urticarial papules and plaques (98% of cases), with over half developing polymorphous features including erythema, vesicles, and eczematous lesions 1
• Primarily affects the abdomen and proximal thighs (97% of cases) 1
• Self-limiting condition that resolves within approximately 4 weeks 1

Treatment Algorithm

First-Line Treatment

1. Topical therapy:
   • Low to medium potency topical corticosteroids 2, 1
   • Emollients for skin hydration 2, 1
   • These measures are sufficient to control symptoms in most patients 1

Second-Line Treatment

1. For severe or refractory cases:
   • Oral prednisolone 3
   • Starting dose: Based on severity (typically 20-40 mg daily)
   • Taper gradually as symptoms improve
   • Note: Prednisolone is preferred over betamethasone or dexamethasone as it is 90% inactivated by the placenta 4

Additional Supportive Measures

1. Antihistamines:

   • First-generation (e.g., chlorpheniramine) or second-generation (e.g., cetirizine, loratadine) antihistamines may be considered for severe pruritus 5
   • These have demonstrated safety during pregnancy 4

2. In extremely severe cases:

   • Early delivery may be considered if near term and symptoms are intolerable 3

Special Considerations

Safety of Medications During Pregnancy

• Topical corticosteroids: Safe during pregnancy, especially low to medium potency formulations 2
• Oral prednisolone: Current evidence suggests no significant increased risk of stillbirth, preterm delivery, or congenital malformations 4
• Antihistamines: Both first and second-generation antihistamines have accumulated sufficient observational data demonstrating safety 4

Postpartum Considerations

• PEP may persist into the postpartum period in some cases 3
• Women who required oral prednisolone during pregnancy may relapse during breastfeeding and require additional systemic therapy 3
• Prednisolone is compatible with breastfeeding 4

Monitoring and Follow-up

• Regular assessment of symptom control
• Monitoring for potential side effects of medications, particularly with systemic corticosteroids
• Reassurance about the benign, self-limiting nature of the condition with favorable outcomes for both mother and fetus 1

Important Caveats

• PEP is not associated with adverse maternal or fetal outcomes, unlike some other pregnancy dermatoses 2, 6
• Distinguish PEP from pemphigoid gestationis, which can have similar presentation but requires different management 6
• Excessive maternal weight gain has been associated with PEP in 78% of cases 1
• The condition typically resolves spontaneously after delivery, though some cases may require continued treatment postpartum 3

Remember that while PEP can cause significant discomfort, it poses no risk to the pregnancy outcome and can be effectively managed with appropriate treatment.