181 Efficacy of Petrolatum of petrolatum under gloves to be worn at bedtime for treatment of eczematous hands. Paraffin-based containing emollients are recommended for the treatment of the severely dry skin found in ichthyosis (38). AD patients experience a higher frequency of skin infections (39,40). Thus, preservation of the barrier is important to protect against further inflammation. Interestingly, patients with AD experience many more skin infections than those afflicted with psoriasis, despite the commonality of a perturbed barrier. It has been suggested that the decreased production of antimicrobial peptides (AMPs) in AD patients may explain the increased susceptibility to skin Infection (41). Surprisingly, PJ has been found to upregulate AMP production in the skin of both healthy patients and patients with AD (17). In the Czarnowicki study, petrolatum, applied under occlusion, significantly increased gene expression of AMPs (including members of the S100 family and cathelicidin) and cytokines (IL1b, Il6, Il8, TNFa), as compared with occlusion alone (17). Increases in AMP protein levels were observed in both subjects with AD and subjects without AD, although upregulation was higher in the subjects without AD. Epidermal differentiation was also assessed in the study. Petrolatum occlusion resulted in an increase in filaggrin and loricrin protein and improvement in the overall differentiation process as assessed by hematoxylin and eosin staining. Finally, decreases in T cell and dendritic cell counts were observed in the AD cohort. The authors hypothesized that the upregulation of the Th17 pathways that underlie the increase in AMP could be mediated by upregulation of the arylhydrocarbon receptor. However, very few polyaromatic hydrocarbons remain in VPJ after purification, and topical hydrocarbons do not penetrate intact or damaged skin (16,10). Overall, the study demonstrates that the benefits of PJ in AD may extend well beyond mere moisturization. BABY SKIN Infant skin (i.e., 3–12 months) has been shown to have different water handling properties versus adult skin, suggesting the barrier properties of infants are not identical to those of adults. Hydration and water content are higher in infants, as measured by Raman spectroscopy and conductance measurements (42). However, in this same study by Nikolovski et al., water-holding capacity was lower, as evidenced by lower levels of natural moisturizing factors and higher TEWL (42). Thus, protecting the delicate and maturing skin of infants is important. PJ is frequently recommended to prevent diaper dermatitis (43,44) and is a favorite for use in pediatric AD (36). Additionally, it is commonly used and recommended by midwives across Africa for skin protection properties before, during, and after birth, as it can be purchased at many local stores at prices typically lower than those of baby lotions (45,46). AD is a common chronic inflammatory skin condition that typically begins in early childhood. Prevalence is at 20% in some countries and is increasing (47). Prophylactic use of daily moisturizers from birth is now widely recognized as a cost-effective means of reducing the risk of developing AD in high-risk infants (48–50). Petrolatum was deemed the most cost-effective preventative strategy when tested on newborns at high risk of developing AD (36). Routine use of moisturizers has been shown to reduce the severity of symptoms in children with mild to moderate AD (51,52). As with adults, the proposed mechanisms for the beneficial effect of emollients in children and infants are focused on barrier repair and decreased TEWL. However, moisturization has also been shown to improve microbial diversity and reduce colonization in patients with AD. In one study, topical treatment with PJ-containing

182 JOURNAL OF COSMETIC SCIENCE ointment decreased TEWL, severity of dermatitis, and bacterial colonization of axillary skin in premature infants treated twice daily (53). Studies by Glatz et al. (54) showed that early daily use of a petroleum-based emollient led to a more beneficial skin microbiome in high-risk newborns. Microbial diversity increased and more closely mirrored non-AD sites in both adults and infants with AD after emollient treatment (55). Numerous studies have shown that moisturization is useful in prevention and treatment of AD in infants and children through improvement in barrier properties and through modulation of skin microbiome. However, petrolatum and petrolatum-containing products have an additional benefit in accelerating barrier recovery and stimulating the innate immune response. WOUND HEALING Although commonly used for minor wounds or burns, topical antibiotic dressings do not offer any advantages over PJ alone and may cause irritation due to cross-sensitization or allergic contact dermatitis. They also present a risk for antibiotic resistance (56–59). Petrolatum is routinely used postoperatively as an alternative to antibiotic ointments to promote wound healing and prevent infections. In a large, randomized, controlled clinical study, no significant differences in infection rates and healing characteristics were found between petrolatum and bacitracin for skin healing post-procedurally (56). Bacitracin was shown to induce allergic contact dermatitis in up to 13% of patients, whereas allergic reactions to petrolatum are rare. Bacitracin has reportedly caused contact anaphylaxis in several cases, while there have been no documented cases for VPJ (60–63). Smack and colleagues concluded that “white petrolatum is an effective, safe wound care ointment for ambulatory surgery” and furthered stated that PJ is highly cost-effective compared to antibiotic ointments. PJ was the highest (69.4%) recommended emollient post-surgically by more than 850 members of the American College of Mohs Surgery (64). In a small comparative study of patients who had undergone Mohs surgery, the authors found that the surgical wounds treated with PJ resulted in significantly less erythema (12%) than did those treated with Aquaphor® (Beiersdorf Inc., Wilton, Connecticut) healing ointment (52%). This was presumably due to differences in formulation where other allergens may have been present (65). More recently, Saco and colleagues performed a meta-analysis and found no significant difference in postoperative wound infection rates between topical antibiotics and petrolatum/paraffin (66). PJ is also indicated for treatment of partial thickness burns. In one clinical study, it was as effective as silver sulfadiazine as measured by time to reepithelialization and incidence of infection and contact dermatitis, and it was significantly better than silver sulfadiazine gauze dressing for wound adherence and ease of use (65,67). The authors concluded that PJ was a cost-effective alternative for minor superficial partial thickness burns. In patients with extensive burn wounds, application of a petrolatum-based moisture dressing for microskin autografting on granular tissue showed improvement in cosmetic appearance, with less blood loss, shorter surgical duration, and lower cost of surgery (68). Treatment for toxic epidermal necrolysis wounds by gauze infused with PJ was found to be a good alternative for disease management, decreasing pain without impacting wound healing time as compared with more expensive treatments (69). Petrolatum was equally effective in prevention of postoperative auricular suppurative chondritis as gentamicin. Campbell et al. concluded it was cost-effective and potentially less irritating (58).