Routine Emollient Therapy with Coconut Oil in Preterm Infants and Allergic Sensitization at 1-Year Corrected Age Open Access

Following a pilot trial demonstrating clinical benefit for very preterm infants, topical coconut oil was introduced into routine care [1]. Depending on gestational age at birth, 5 mL coconut oil is applied to the entire integument (except face, scalp, and areas around monitoring leads and any invasive devices or dressings) two to four times daily, reduced to once daily when nursed outside the incubator and until 37 weeks gestation or hospital discharge, according to parental preferences [2]. Since 2017, more than 2,000 infants at our institution have received this prophylactic intervention without adverse events.

While the introduction of potential allergens into the infant diet has seen a paradigm shift in the last decade, allergy guidelines commonly recommend avoidance of topical application of food products due to possible transdermal sensitization [3]. True allergic reactions to coconut, botanically distinct from tree nuts and peanuts, are rare. Chemical derivates of coconut oil fatty acids commonly present in cosmetic products, but not in pure coconut oil, can cause contact allergic dermatitis. Data on allergic sensitization in preterm infants are scarce and skin prick testing usually does not include coconut oil and/or coconut extract. Here, we expand our previous clinical observations on the effects of topical coconut oil with characterization of allergic sensitization to common allergens, including coconut oil and extract, in a cohort of very preterm infants at corrected age 15 months [4, 5].

This study was approved by the institutional human research Ethics Committee (RGS0000005250) and written informed consent was obtained prior to study participation. All infants in the study cohort received per protocol topical coconut oil during their neonatal admission. Along with the invitation for routine follow-up at 12 months corrected age, the time of highest incidence of allergic conditions including eczema and food allergies, we offered families an allergy assessment. Participants underwent a basic physical assessment, and if signs of atopic dermatitis were present at the appointment, the validated Eczema Area and Severity Index assessment was done [6]. Allergy questionnaires were administered to determine family history of atopy (eczema, asthma, allergic rhinitis, and food allergy) for parents and infants. Skin prick testing to coconut oil (same low protein neonatal skin care product) and coconut extract, as well as other common allergens for this age-group: cashew, cow’s milk protein, egg white, dust mite, peanut, and rye grass (ALK-Abello, Round Rock, TX, USA).

Out of 107 recruited families, 90 children, born at a median gestational age of 28.3 weeks (range 23.3–34.1), completed the allergy assessment at a median corrected age of 15 months (range 9.4–21.8). Twelve were lost to follow-up, and five withdrew from the study prior to assessment (Table 1).

Out of the 90 children with completed assessments, 43 (47.8%) had a history of having had dry, scaly, and/or red skin in the past, 22 (24.4%) had received a physician diagnosis of eczema, and 21 (23.3%) received eczema treatment in the past month; 20 (22%) children presented with mild and 2 (2.2%) children with moderate eczema lesions at study assessment. The frequency of any self-reported allergic condition was substantially higher in parents, with 71% of children having at least one parent with asthma, eczema, food allergy, or allergic rhinitis; this was more common in mothers (60%) than fathers (33%), and in 23.3% at least one of these conditions was reported for both parents.

All participants underwent skin prick testing, and none of the children were sensitized to coconut oil or extract. Positive skin prick test results (>3 mm) were seen in 8/90 children (8.9%), most commonly to egg (6/90, 6.7%), peanut (4/90, 4.4%), cashew (2/90, 2.2%), and dust mite (2/90, 2.2%). Among children with positive tests, 5/8 (62.5%) were sensitized to more than one antigen (Table 2) and 5/8 (62.5%) also had received a physician diagnosis of eczema. Importantly, none of the children were sensitized to coconut oil or extract. Further, the majority of children in our study (66%) had a history of consuming food containing coconut, without symptoms.

Our study provides important information on coconut sensitization in a cohort of preterm infants exposed to early-life topical coconut oil and complements our previous reports [4, 5]. While the sample size of this preterm infant study was limited, the results of less frequent allergic sensitization compared to reported incidence in term infants (∼15% of 1-year-old children in Australia but substantially higher in at-risk families) as well as male preponderance are consistent with the literature [7‒10]. Importantly, in our cohort, no sensitization to coconut was observed.

We thank the children and their families who participated in this study and all staff that contributed to the implementation of this prophylactic intervention into routine care.

This study was approved by the Child and Adolescent Health Service human research Ethics Committee (RGS0000005250) and parental written informed consent was obtained prior to participation.

The authors have no conflicts of interest to declare.

The study was supported by a Northern Star Resources community grant, as well as in-kind support from the Department of Allergy and Immunology and the Neonatal Directorate.

Jennifer Mountain provided overall coordination of the project and provided intellectual input. Terri Williams, Jemma Weidinger, Jessica Metcalfe, and Samantha Thomas coordinated and conducted the allergy assessments and provided intellectual input. Andrew Currie and Michael O’Sullivan conceptualized the study, assisted with its implementation, and edited the manuscript drafts. Tobias Strunk conceptualized the study and wrote the initial and subsequent manuscript drafts. All authors approved the final manuscript version.

The data that support the findings of this study are not publicly available due to ethical reasons but are available from the corresponding author upon reasonable request.