Pruritic urticarial papules and plaques of pregnancy (PUPPP)

Diagnosis: Pruritic urticarial papules and plaques of pregnancy (PUPPP)

Clinical History

Pruritic, erythematous wheals that resolve within 24 hours. Duration (6 weeks = chronic). Triggers: medications, foods, infections, physical stimuli. Angioedema presence.

Treatment

First-line: second-generation H1 antihistamine (cetirizine, loratadine, fexofenadine). Step up: increase dose up to 4× standard. Add-on: omalizumab for refractory CSU. Short-course systemic corticosteroids for severe acute flares only.

Differential Diagnosis

• Urticarial vasculitis • Drug eruption • Contact dermatitis • Erythema multiforme • Bullous pemphigoid (urticarial phase) • Insect bites (papular urticaria) • Dermatographism • Mastocytosis

Key Learnings

• Individual wheals resolve within 24 hours without residual marks — if lasting >24 hours, consider urticarial vasculitis • Acute urticaria (6 weeks): usually idiopathic; autoimmune mechanism in ~40% • CSU workup: CBC, ESR/CRP, TSH; extensive testing is low-yield • Omalizumab (anti-IgE) is FDA-approved for CSU refractory to antihistamines • Angioedema: deeper involvement — ACE inhibitor-induced angioedema is bradykinin-mediated (antihistamines won't work) • Second-generation antihistamines at up to 4× standard dose before escalating therapy

Tags: dermatology, kodachrome, Pruritic urticarial papules and plaques of pregnancy (PUPPP), PUPPP