Dear Editor,

Seborrheic dermatitis (SD) is a common chronic inflammatory dermatosis affecting the face, scalp, and upper trunk and has a significant negative impact on quality of life [1]. The pathogenesis of SD is controversial, but Malassezia species are thought to play a role. The exact contribution is unclear with proposed mechanisms involving both yeast density and immune response [2]. Malassezia species are normal skin commensals, but in a pathogenic role they can precipitate pruritus, scale, erythema, and dyspigmentation seen in SD. Transition to a pathogenic role may be promoted by lipids such as those found in common hair oils [3]. SD is common in black patients [4]. Here, we discuss the potential association between the use of hair oils in black patients and SD.

Malassezia is a lipophilic lipid-dependent yeast. Cradle cap in neonates may represent the initial colonization of Malassezia; however, activity decreases until puberty when sebaceous gland activity and oil production increase [5]. The organism consumes fatty acids necessary for proliferation and leaves behind unsaturates that may cause irritation (Ro). In order to culture Malassezia in a laboratory setting, a lipid supplement, such as olive oil, is required [6]. Although no clinical studies have been done exploring the effects of hair oils on SD, in vitro studies evaluating the effect of oils on Malassezia growth have been performed. One study investigated the effects of corn oil, butter, olive oil, coconut oil, oleic acid, and castor oil on M. furfur growth. Dextrose medium without added fatty substances was maintained as the control. After 7 days, M. furfur grew well in butter, followed by corn oil, olive oil, coconut oil, oleic acid, and castor oil [7]. Dextrose medium without added fatty substances demonstrated poor Malassezia growth. Given this response, we posit that the use of common hair oils, such as olive oil and coconut oil, on the scalp may propagate Malassezia growth, exacerbating SD.

Natural oils have long been used in skin of color patients for hair and skin care. In patients with tightly coiled hair curl patterns, the lubricating effects of oils reduce fiber friction and the abrasive damage caused by grooming [8]. Some oils may also penetrate the hair and fill gaps protecting against surfactant damage from shampoos [9].

Although oils are beneficial for the hair shaft, by tradition, many patients of African descent lubricate or “grease” the scalp [10]. This is often done with oils such as coconut oil, jojoba oil, olive oil, and shea butter. In the black community, these oils are thought to promote scalp health and hair growth, as well as treat SD, misinterpreted as “dry scalp” due to the presence of scale.

Recent literature has reported increased incidence of SD among African Americans and West Africans may be due to hair pattern, infrequent shampooing, and excessive use of hair oils and pomades [11]. Tighter curl patterns impede sebum travel down the hair shaft leading to oil build-up on the scalp. This coupled with additional oils applied to the scalp and infrequent shampooing regimens may lead to increased Malassezia density and a higher risk of SD.

Management can be challenging using traditional shampoos alone. Once weekly shampooing should be recommended; however, leave-in treatment vehicles such as foams, oils, and ointments allow for more frequent application and should also be considered to accommodate less frequent hair washing. Vehicle should be selected based on patients’ hair styling preferences.

SD is common in black patients and can impact quality of life. More research evaluating the effects of different hair oils and oil vehicles in SD is needed. Traditional practice of lubricating or “greasing” the scalp for perceived hair health and to conceal scale may be contributing to the severity and chronicity of SD. Though oils can be beneficial for the hair, they may be associated with worsening SD when applied to the scalp. Providers should recommend patients avoid oils on the scalp and instead focus on the distal hair shafts, which are more susceptible to damage and may benefit from oil application.

Tiffany Mayo received honorarium as a consultant for Arcutis, Bodewell, Janssen, Lilly, Novartis, and Pfizer. Boni Elewski received honorarium as a consultant for Amgen, Arctic, Boehringer Ingelheim, BMS, Celgene, Leo, Lilly, Novartis, UCB, and Valeant (Ortho Dermatology).

The authors have received no external funding.

Tiffany Mayo made contributions to conception, drafting, and editing of the manuscript. Jewell Dinkins made contributions to drafting and editing of the manuscript. Boni Elewski made contributions to conception, drafting, and editing of the manuscript.

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