The purpose of this study is to determine the dermal sensitization potential of azelaic acid pre-foam formulation.

In an induction phase a three times weekly exposure over three weeks will be performed, followed by a resting phase. In a following challenge phase single exposure will be performed again and potential skin reactions observed. If skin reactions occur an optional re-challenge phase may be performed.

Inclusion Criteria:

• healthy volunteers
• male or female subjects
• aged 18 - 65 years
• ability to understand and fulfill the study requirements

Exclusion Criteria:

• affected skin in designated test area
• pregnancy or lactation
• not willing to comply with study requirements