Inclusion Criteria:

• Adult subjects >18 years of age at screening.
• Previous diagnosis by a physician of atopic dermatitis, psoriasis, vitiligo, or alopecia areata.
• Visible lesions and willingness to photograph weekly using their smartphone
• Availability of a smartphone

Exclusion Criteria:

• Has any physical attributes or skin conditions that in the opinion of the investigator might interfere with the evaluation of lesions (i.e., pigmentation, tattoos, extensive scarring, excessive hair growth or acne)
• Has other clinically relevant illness that could interfere with healing of lesions (e.g. keloid scaring)
• Current or previous malignant disease, including malignant melanoma and basal cell carcinoma, within 5 years
• Some patients may have more than one of the four conditions. This is not an exclusion criterion per se but must be recorded.