Observational StudyCollection of Samples From Subjects With Various Skin Conditions and Healthy Volunteers

Inclusion Criteria:

All subjects:

1. Subject is willing to participate and is capable of giving informed consent. Note: Consent must be obtained prior to any study-related procedures.
2. Subject must be willing to comply with all study procedures and must be available for the duration of the study.

Healthy volunteers:
3. Male or female subject aged 18 years or older, at the time of consent.
4. Subject is in good general health, according to the investigator's judgment.

Subjects with Acne:
5. Male or female subject aged 18 to 45 years old, inclusive, at the time of consent.

Subjects with AD:
6. Male or female subject aged 18 years or older, at the time of consent.
7. Subject has clinically confirmed diagnosis of active AD, according to Hanifin and Rajka criteria.

Subjects with CHE:
8. Male or female subject aged 18 years or older, at the time of consent.
9. Subject has at least a 6-month history of CHE before Screening (information obtained from medical chart or subject's physician, or directly from the subject).

Subjects with HS:
10. Male or female subject aged 18 years or older, at the time of consent.
11. Subject has a clinically confirmed diagnosis of active HS with a disease duration of ≥ 6 months before screening as determined by the investigator through subject interview and/or review of the medical history.

Subjects with PPP:
12. Male or female subject aged 18 years or older at the time of consent.
13. Subject has at least a 6-month history of PPP as defined by the presence of pustules on palms and/or soles, but without evidence of infection on palms and soles (information obtained from medical chart or subject's physician, or directly from the subject).

Subjects with psoriasis:
14. Male or female subject aged 18 years or older, at the time of consent.

Exclusion Criteria:

All subjects:

1. Subject is a female who is pregnant or who is planning to become pregnant during the study.
2. Subject has a history of skin disease or presence of skin condition that, in the opinion of the investigator, would interfere with the study assessments.