Linking Epidermal Barrier Function With Anti-Oxidant Defense Mechanisms in Skin Conditions

Up to 300 subjects with chronic skin conditions (including but not limited to atopic
dermatitis (AD), contact dermatitis, hidradenitis suppurativa (HS), and psoriasis) and 100
healthy subjects meeting the inclusion criteria will be enrolled. Medical records will be
reviewed pertaining to the subject's diagnosed chronic skin condition and specific
therapeutic interventions.

For atopic dermatitis subjects, AD severity will be assessed using Eczema Area and Severity
Index (EASI). Study sites will be chosen by the investigator. One lesional and one
nonlesional site on the trunk, upper, or lower extremities will be selected. Digital photos
of the study skin site(s) will be taken. Skin barrier function indices (transepidermal water
loss, pH, sebum and hydration levels) of an active lesion and adjacent nonlesional skin will
be measured using noninvasive skin barrier measurement devices.

For subjects with other chronic skin conditions such as contact dermatitis, HS or psoriasis,
photos of the selected study sites will be taken. No skin barrier measurements will be
performed.

For all subjects, two 3mm punch biopsies will be performed over the selected skin sites. One
biopsy will be performed over an active lesion and another on adjacent nonlesional skin.
Tissue will be sent out for immunohistochemical staining to study the expression anti-oxidant
biomarkers. Five mL of peripheral venous blood will be collected for immunoassay to measure
the level inflammatory cytokines.

For healthy subjects, digital photo of the study skin site(s) over either the trunk, upper,
or lower extremities will be taken. Skin barrier function indices (transepidermal water loss,
pH, sebum and hydration levels) of skin be measured using noninvasive skin barrier
measurement devices. One 3mm punch biopsy will be performed over the same skin site that skin
barrier measurements were performed. Tissue will be sent out for immunohistochemical staining
to study the expression anti-oxidant biomarkers. Five mL of peripheral venous blood will be
collected for immunoassay to measure the level inflammatory cytokines.

Inclusion Criteria:

Male and female 18 to 99 years of age. Chronic skin condition (including but not limited to
atopic dermatitis, contact dermatitis, hidradenitis suppurativa, and psoriasis) with at
least one active skin lesion Healthy skin (defined no clinical evidence or diagnosis of
inflammatory skin conditions)

Exclusion Criteria:

Subjects who are unable to comply with study procedures.