Safety and efficacy of personal care products containing colloidal oatmeal

Abstract

Background: Colloidal oatmeal is a natural ingredient used in the formulation of a range of personal care products for relief of skin dryness and itchiness. It is also used as an adjunctive product in atopic dermatitis. The safety of personal care products used on vulnerable skin is of particular importance and the risk of developing further skin irritations and/or allergies should be minimized.

Methods: In a series of studies, we tested the safety of personal care products containing oatmeal (creams, cleansers, lotions) by assessing their irritant/allergenic potential on repeat insult patch testing, in safety-in-use and ocular studies using subjects with nonsensitive and sensitive skin. We also tested the skin moisturizing and repair properties of an oatmeal-containing skin care product for dry skin.

Results: We found that oatmeal-containing personal care products had very low irritant potential as well as a very low allergenic sensitization potential. Low-level reactions were documented in 1.0% of subjects during the induction phase of repeat insult patch testing; one of 2291 subjects developed a persistent but doubtful low-level reaction involving edema during the challenge phase in repeat insult patch testing. No allergies were reported by 80 subjects after patch testing after in-use application. Sustained skin moisturizing was documented in subjects with dry skin that lasted up to 2 weeks after product discontinuation.

Conclusion: Our results demonstrate that colloidal oatmeal is a safe and effective ingredient in personal care products. No allergies were reported by consumers of 445,820 products sold during a 3-year period.

Keywords: Avena sativa; allergenic dermatitis; atopic dermatitis; colloids; irritant dermatitis; protective agents; skin care.

Figures

Figure 1

Skin hydration increases during and after use of oatmeal-containing cream. Notes: Hydration of the forearm increased significantly during the application period (days 1–28) and afterwards (day 42) compared with baseline. Hydration of the leg increased significantly more compared with the control area at all time points.

Figure 2

Surface area of dead cells and desquamation index diminish with use of oatmeal-containing cream. Surface of dead cells (A) and desquamation rate (B) were compared with baseline for the forearm area and their reduction is indicated as percentage improvement. Data derived from leg measurements was compared with the control area for surface of dead cells (C) and desquamation rate (D). Abbreviation: NS, not statistically significant.

Figure 3

Clinically assessed parameters improve with use of oatmeal-containing cream. Note: At all time points, the three parameters assessed, ie, skin dryness, appearance of squamae, and skin roughness, were significantly more improved on the treated leg area compared with the control area.

Figure 4

Subjective evaluation of effect on signs of skin dryness. Note: The percentage of patients who reported a positive effect on skin dryness is depicted (combination of answers “agree” and “rather agree”).