What is pruritic urticarial papules and plaques of pregnancy (PUPPP) and what are the recommended treatments?

PUPPP in Pregnancy

PUPPP (Pruritic Urticarial Papules and Plaques of Pregnancy), also known as Polymorphic Eruption of Pregnancy (PEP), is a benign, self-limited inflammatory skin condition that typically affects primigravidas in the third trimester, presenting with intensely pruritic urticarial papules and plaques on the abdomen (especially within striae) and proximal thighs, requiring only symptomatic treatment with topical corticosteroids and oral antihistamines. 1, 2

What is PUPPP?

PUPPP is the most common dermatosis of pregnancy, characterized by:

• Onset: Third trimester (89% of cases), though postpartum onset can rarely occur 3, 4, 5
• Population: Predominantly primigravidas (72%) 3
• Clinical presentation: Pruritic urticarial papules and plaques that begin on the abdomen, particularly within striae distensae, with characteristic periumbilical sparing 5
• Distribution: Spreads to proximal thighs, buttocks, and occasionally extremities 1, 3
• Natural history: Self-limited, resolving spontaneously near delivery or within 2-3 weeks postpartum 2, 3, 6

Key Distinguishing Features from Other Pregnancy Dermatoses

When evaluating pruritic conditions in pregnancy, PUPPP must be differentiated from conditions with fetal risk 1:

• PUPPP: Rash present, no fetal risk, benign course 2, 6, 7
• Intrahepatic Cholestasis of Pregnancy (ICP): Pruritus without rash (palms/soles predominant, worse at night), elevated bile acids, significant fetal risk including stillbirth 1, 7
• Pemphigoid Gestationis: Vesicles and bullae, positive immunofluorescence, fetal risks 1, 7
• Atopic Eruption of Pregnancy: Eczematous rash on face, neck, flexural areas 1

Diagnostic Approach

Clinical diagnosis is sufficient in typical presentations. Look for:

1. Timing: Third trimester onset (or rarely postpartum)
2. Morphology: Urticarial papules and plaques, not vesicles or bullae
3. Distribution: Abdomen (especially striae) with periumbilical sparing, then thighs
4. Associated factors: Primigravida, multiple gestation (50% of cases), excessive weight gain, high BMI 3, 5

Skin biopsy is rarely needed but shows nonspecific mild lymphohistiocytic perivascular infiltrate with variable eosinophils. Direct immunofluorescence is negative, which helps exclude pemphigoid gestationis 2, 3, 6.

Laboratory testing is unremarkable - no elevated bile acids (unlike ICP), normal liver function tests 3, 5.

Treatment Algorithm

First-line treatment (start immediately):

• Topical corticosteroids: Medium to high potency (e.g., triamcinolone 0.1% or betamethasone 0.05%) applied to affected areas twice daily 2, 6, 8
• Oral antihistamines: Non-sedating H1 antihistamines during the day (cetirizine 10 mg or loratadine 10 mg daily) 9, 6
• Sedating antihistamines at night: Chlorphenamine 4-12 mg or hydroxyzine 10-50 mg to improve sleep 9

Note on antihistamine safety in pregnancy: While best avoided in first trimester, chlorphenamine has the longest safety record in pregnancy. Cetirizine and loratadine are FDA Pregnancy Category B 9. Hydroxyzine is specifically contraindicated in early pregnancy per UK guidelines 9.

Emollients and supportive care: Liberal use of moisturizers 3

Expected response: Symptoms typically resolve within 2-3 weeks with treatment, often coinciding with delivery 3, 6

Alternative treatments if standard therapy insufficient:

• Intramuscular autologous whole blood injection has been reported effective in small case series, though this remains experimental 10

Critical Management Points

Reassurance is paramount: PUPPP poses no maternal or fetal risks - no increased risk of prematurity, stillbirth, or congenital malformations 2, 3, 6, 8, 7. This distinguishes it from ICP and pemphigoid gestationis.

Do not use systemic corticosteroids: Unlike other pregnancy dermatoses, PUPPP responds well to topical therapy alone. Oral corticosteroids are unnecessary and expose the patient to avoidable risks 11, 6.

No need for early delivery: PUPPP is not an indication for preterm delivery 2, 6.

Postpartum monitoring: Lesions should resolve within weeks of delivery. If pruritus persists beyond 6 weeks postpartum, evaluate for other causes including chronic liver disease 12.

Common Pitfalls to Avoid

1. Missing ICP: Always check bile acids if pruritus without typical PUPPP rash, as ICP carries significant fetal risk requiring early delivery 1, 12
2. Confusing drug reactions: Postpartum PUPPP can be mistaken for drug reactions (e.g., to LMWH after cesarean section). Classic distribution with periumbilical sparing and striae involvement confirms PUPPP 5
3. Over-treating: Systemic corticosteroids are not indicated for PUPPP 6
4. Under-recognizing postpartum onset: While rare, PUPPP can present in the immediate postpartum period 4, 5