Emulsions Containing Echinacea Extract Reduce Body and Scalp Pruritis

Pruritis (itching) is a common symptom of inflammatory skin diseases and is strongly associated with dry skin. Topical emollients to replenish lipids and moisturizers to hydrate the skin are first-line treatments; however, the effects are often unsatisfactory. Treatment for three months with a water-in-oil (w/o) emulsion containing a proprietary echinacea (Echinacea purpurea, Asteraceae) root extract was found to significantly alleviate pruritis associated with subacute or chronic atopic eczema (AE) in one clinical study; however, the effectiveness of the echinacea w/o emulsion in the treatment of acute or chronic pruritis not associated with AE has not been clinically assessed. Although w/o emulsions are usually more effective than oil-in-water (o/w) emulsions for the treatment of pruritis, w/o emulsions are not cosmetically acceptable therapeutics for dry, itchy scalp. Therefore, a novel o/w emulsion containing echinacea extract and a shampoo containing echinacea extract were developed. The purpose of this three-part open-label, non-randomized, uncontrolled study was to evaluate the three aforementioned products in the treatment of pruritis and dry, itchy scalp.

The three studies were conducted in Freiberg, Germany (study initiation and completion dates, and recruitment methods were not reported). The inclusion criteria were different for each study; however, the exclusion criteria were largely the same and the same outcome measures were used in all three studies. The outcome measures were as follows: (1) a dermatologist assessed skin tolerance (erythema, edema, dryness, papules, pustules, and fissures), (2) participants were interviewed by a dermatologist regarding intensity, burning, and skin tension, and (3) participants completed a questionnaire assessing intensity, duration, occurrence, and burden.

Study 1: Echinacea W/O Emulsion for Pruritis not Associated with AE

The two-week study included otherwise healthy adults (n = 55, aged 20-78 years) with acute or chronic pruritus not associated with AE. Excluded participants were using topical medication in the test area within one month of study entry, were using systemic medication with immunomodulators and/or chemotherapeutic agents within four weeks of study entry, were using systemic antibiotics or had a change in anti-inflammatory agents two weeks before starting the study, had severe disorders within the last 12 months, were pregnant or breastfeeding, participated in other studies concurrently or during the two weeks before starting this study, or participated in a study evaluating a pharmaceutical preparation within four weeks prior to starting the study.

The participants (18 male and 37 female) were instructed to refrain from changing their skincare and cleansing habits for 7 days prior to starting the study and refrain from using any leave-on product on the body 24 hours before the study began and for the duration of the study. Participants were instructed to apply the w/o emulsion with lipophilic Echinacea extract (Linola Plus Lotion; Dr. August Wolff GmbH & Co. KG Arzneimittel; Bielefeld, Germany) over the entire body (face optional) at least once daily for two weeks. Compliance was assessed using study diaries and weighing the product at the start and end of treatment

The dermatologist assessment showed a significant decrease in erythema and dryness (P < 0.0001 for both); 33% of participants had a significant decrease in erythema and 76% had a significant decrease in dryness. The interview assessment showed a significant decrease in pruritus intensity (P < 0.0001), burning (P < 0.028), and skin tension (P < 0.0001). Specifically, pruritis was decreased by 93% of participants, and skin tension was decreased by 76% of participants. Based on the results of the questionnaire, the majority of participants had no perceptible pruritus (62%) or very slightly perceptible pruritus (18%) after two weeks of treatment, and 93% of participants had some reduction in pruritis. The burden due to pruritis was decreased by 91% of participants (there was a significant decrease in burden score compared with baseline, P < 0.0001). The duration of pruritis was also shortened compared with baseline. After two weeks of treatment, pruritus was not present in 62% of participants, 35% of participants had “short term” pruritus, and constant pruritus was no longer reported. The antipruritic effect started immediately and lasted for 24 hours according to 69% of the participants. Approximately two-thirds of the participants reported that the product spread well and absorbed quickly.

Study 2: O/W Emulsion with Echinacea Extract for Dry, Itchy Scalp

Adults (n = 33, aged 24-69 years) who used hair tonic for dry scalp and had itchy scalp prone to AE/atopic dermatitis participated in the four-week study. Exclusion criteria were similar to Study 1 with the addition of excluding users of sour hair rinse and those with other dermatological disorders on the scalp. The low-fat o/w emulsion containing the lipophilic Echinacea extract was applied to the scalp once daily in the evening for four weeks. Participants were instructed to refrain from changing their shampoo and hair care products at least seven days before the start of the study and during the study. Once the product was applied, participants were to refrain from washing their hair until the next morning. On the study visit days, participants were requested to wash their hair at least three hours before the visit and not use hair styling products. Outcome measures and scalp skin hydration were assessed at baseline, two weeks, and four weeks.

The dermatologist assessment revealed the following: significant reduction of erythema in 45% of participants at two weeks and 61% of participants at four weeks (P < 0.0001), significant reduction of dryness in 67% of participants at two weeks and 85% of participants at four weeks (P < 0.0001), significant reduction of scaling in 57% of participants at two weeks and 61% of participants at four weeks (P < 0.0001), and papules were no longer observed at two weeks, constituting an improvement in 58% of participants. Skin hydration was significantly decreased at two weeks (P < 0.05) but significantly increased at four weeks (P < 0.05) compared to baseline. Based on the interview responses, reduction of pruritis was reported by 79% of participants at two weeks and 85% of participants at four weeks; reduction of burning was reported by 21% of participants at two weeks and 27% of participants at four weeks; and reduction of skin tension was reported by 48% of participants at two weeks and 51% of participants at four weeks. The questionnaire responses indicated that a majority of participants had reduced pruritus (94%), burning (89%), tension (83%), skin dryness (88%), and dandruff (83%) at four weeks. The fact that the number of participants who experienced improvements increased between week two and week four suggests that the treatment may provide long-term benefits. Participants were satisfied with the cosmetic properties of the product, and there was no unusual effect on hair after washing.

Study 3: Shampoo with Echinacea Extract for Chronically Itchy Scalp

Adults (n = 33, aged 20-70 years) with chronically itchy and normal-to-dry scalp participated in the four-week study. Exclusion criteria were similar to Study 2. Participants used a shampoo with the echinacea extract for four weeks (it is unclear how often they used it). Hair coloration (dying) was prohibited for at least 14 days prior to study entry and during the study. Participants were instructed to refrain from changing their hair care and styling products for at least seven days prior to study entry and during the study. Outcome measures were assessed at baseline and at four weeks.

The dermatologist assessment of tolerance showed that after four weeks of regular use there was a significant decrease in scalp dryness (P < 0.0001), and scaliness (P = 0.0002), and there was no significant effect on erythema, edema, and papules. In 70% of participants, pruritis, burning, and tension “lasted shorter, disappeared, or was distinctly lower.”

The authors conclude that both the w/o and low-fat o/w emulsions with echinacea extract significantly reduced objective and subjective measures of pruritis on the body and scalp, and exhibited excellent tolerability. “In addition, the improvement was noticeable already after the first treatment and further improved within 14 days of product use.” The limitations of these studies include the lack of control groups and blinding, small sample sizes, and short study durations. The authors conclude that “these medical skincare products show promise as adjuvant therapy to alleviate pruritus of body or scalp independent from underlying causes. A future study using both products (shampoo and o/w emulsion) will show whether beneficial effect can be further improved.”

The studies were funded by Dr. August Wolff GmbH & Co. KG Arzneimittel and all of the authors are employees of this company. Two of the authors (CA and UK) are named as inventors on the patent application WO 2017/037075A8. The authors report no other conflicts of interest.

Resource:

Kilic A, Harder A, Reich H, Knie U, Masur C, Abels C. Efficacy of hydrophilic or lipophilic emulsions containing Echinacea purpurea extract in the treatment of different types of pruritus. Clin Cosmet Investig Dermatol. November 20, 2018;11:591-602. doi: 10.2147/CCID.S172518.

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