instructions and were provided with tubes of the study product healing ointment along with latex free adhesive bandages to apply at least once daily to the wound and up to 3 times daily. Subjects cleansed the wound daily or as ordered by the physician with a mild cleanser. They did not use any other topical products or medications on the wound. Subjects were given a compliance diary to record the date and time of wound treatments.
Approximately 10-14 days later the patients returned for wound site evaluation for erythema, itching, and pain (0=none or absent, 1 = mild, 2 = moderate, 3 = marked or strong, and 4 = severe or extreme), signs of infection (purulent discharge), and allergic contact dermatitis (erythema, edema, papules, vesicles, bullae, weeping). In the event an allergic contact dermatitis was suspected, the subject was patch tested with the product at a naïve site under occlusive patch conditions. Pictures were taken of the allergic contact dermatitis as determined by the investigators. Patch test sites were evaluated on the following scale 1 hour after removal: 0=none or absent, +/- = equivocal, + = weak, ++ = strong, +++ = severe.
Approximately 10-14 days later the patients returned for wound site evaluation for erythema, itching, and pain (0=none or absent, 1 = mild, 2 = moderate, 3 = marked or strong, and 4 = severe or extreme), signs of infection (purulent discharge), and allergic contact dermatitis (erythema, edema, papules, vesicles, bullae, weeping). In the event an allergic contact dermatitis was suspected, the subject was patch tested with the product at a naïve site under occlusive patch conditions. Pictures were taken of the allergic contact dermatitis as determined by the investigators. Patch test sites were evaluated on the following scale 1 hour after removal: 0=none or absent, +/- = equivocal, + = weak, ++ = strong, +++ = severe.
RESULTS
499 subjects successfully completed the study. 99 subjects were enrolled in cohort 1 in 2010 (Rigel) and 400 subjects were enrolled in cohort 2 in 2019 (Draelos, Rigel, Kircik). No adverse events or serious adverse events occurred during the conduct of the study. Table 1 presents the erythema, itching, and pain incidence where 5.8% of subjects experienced an erythema score of 1 and 1.0% of subjects experienced an itching score of 1. No subjects reported pain. Table 2 presents the incidence of adhesive reactions, purulent discharge, and suspicion of infection. None experienced purulent discharge, and 0.5% of subjects experienced an adhesive reaction. 0.4% experienced induration, but no subjects were found to possess edema, papules, or vesicles. No allergic contact dermatitis was observed and no patch testing was conducted.
DISCUSSION
This study was conducted to assess the incidence of allergic contact dermatitis in 499 subjects who used the study wound healing ointment, containing lanolin alcohol, for wound care following a surgical procedure at one of 3 clinical sites. No incidence of allergic contact dermatitis was observed in 499 subjects. In addition, prior RIPT testing of the study wound healing ointment in 108 and 203 subjects showed no induction of allergic contact dermatitis or cumulative dermal irritation.12 The company has also reported 72 skin irritation complaints received from consumer contacts for more than 53 million units distributed over a 5 year period (2002-2006), corresponding to a very low rate of 1.4 complaints per million units.13
One reason for the lack of allergic contact dermatitis observed with the wound healing ointment in this study may be its formulation with a proprietary highly purified lanolin alcohol (Eucerit®); in Europe, a compounding base is commercially available containing 6% Eucerit® (same LA as AHO) in 93.5% petrolatum, known as Eucerinum Anhydricum (EA). This preparation of LA is not the material found on the dermatology standard patch test tray (Amerchol L101). Uter and Knijp demonstrated higher rates of allergy to the patch test lanolin alcohol than other sources of lanolin alcohol.2,3 Knijp compared the LA used in AHO and EA to the patch test lanolin alcohol (Amerchol L101, 50% in pet, final LA 5%). Amerchol L101 demonstrated an incidence of allergic contact dermatitis 16.7 times greater than that observed for EA.2
Since lanolin alcohol is a natural substance requiring processing and purification, the quality of the materials used in skin care preparations and patch test trays may differ. These data support the observation that LA preparations can differ in allergenicity based on the quality of their purification, demonstrated in a comparison of 30% LA in pet and 6 pharmaceutical grade preparations of LA.14
One reason for the lack of allergic contact dermatitis observed with the wound healing ointment in this study may be its formulation with a proprietary highly purified lanolin alcohol (Eucerit®); in Europe, a compounding base is commercially available containing 6% Eucerit® (same LA as AHO) in 93.5% petrolatum, known as Eucerinum Anhydricum (EA). This preparation of LA is not the material found on the dermatology standard patch test tray (Amerchol L101). Uter and Knijp demonstrated higher rates of allergy to the patch test lanolin alcohol than other sources of lanolin alcohol.2,3 Knijp compared the LA used in AHO and EA to the patch test lanolin alcohol (Amerchol L101, 50% in pet, final LA 5%). Amerchol L101 demonstrated an incidence of allergic contact dermatitis 16.7 times greater than that observed for EA.2
Since lanolin alcohol is a natural substance requiring processing and purification, the quality of the materials used in skin care preparations and patch test trays may differ. These data support the observation that LA preparations can differ in allergenicity based on the quality of their purification, demonstrated in a comparison of 30% LA in pet and 6 pharmaceutical grade preparations of LA.14
