Petrolatum

The Lancet · 2020 · rct · n=2397

Randomized controlled trial (n=2397, 52 weeks): AD at 12 months NO PREVENTION effect in intervention arm.

Cutis · 2012 · systematic review

Review noting that heavy occlusive agents including petrolatum can exacerbate perioral dermatitis by trapping heat, creating anaerobic conditions, and altering the perioral skin microbiome; this is a condition-specific exception to petrolatum's otherwise excellent safety profile; recommends lightweight, non-occlusive moisturizers for POD patients

Journal of Allergy and Clinical Immunology · 2014 · rct · n=124

Randomized controlled trial (n=124, 26 weeks): Cumulative AD incidence at 6 months RR 0.50 95% CI 0.28 to 0.9 p=0.017 50% relative risk reduction.

Journal of Allergy and Clinical Immunology · 2014 · rct · n=118

Randomized controlled trial (n=118, 32 weeks): 32% AD reduction HR 0.48 95 CI 0.27 to 0.86; emulsion emollient vs petroleum jelly control.

JAMA · 1996 · rct · n=922

Randomized controlled trial (n=922, 4 weeks): Infection rate petrolatum 2% vs bacitracin 0.9% NOT statistically different; allergic contact dermatitis petrolatum 0 cases vs bacitracin 4 cases 0.9%.

Journal of the American Academy of Dermatology · 1992 · rct · n=20

Landmark study (n=20): petrolatum accelerated barrier recovery after tape-stripping by 30% compared to untreated control; mechanism is occlusive — petrolatum reduces TEWL by ~98%, allowing endogenous lipid repair without water loss; the most effective single occlusive agent studied; beneficial for most barrier-impaired skin