A Study of A-101 Solution 40% in Subjects With Seborrheic Keratosis.

This is a randomized, double-blind, vehicle-controlled, parallel group study of A-101 Solution 40% compared with Vehicle Solution.

This is a randomized, double-blind, vehicle-controlled, parallel group study. During this study, the investigator will identify 4 eligible SK Target Lesions on each subject on the trunk, extremities and face. The Target Lesions will be treated, by an investigational staff member other than the evaluating investigator, a maximum of two times.

Eligibility Criteria:
Inclusion Criteria:

1. Subject is at least 18 years of age
2. Clinical diagnosis of stable clinically typical seborrheic keratosis
3. Subject has 4 appropriate seborrheic keratosis Target Lesions on the trunk, extremities and face that each are eligible for treatment as defined below:

   * Have a clinically typical appearance
   * Have a PLA of 2 or greater and be a discrete lesion
   * Not be covered with hair which, in the investigator's opinion, would interfere with the study medication treatment or the study evaluations
   * Not be in an intertriginous fold
   * Not be on the eyelids
   * Not be within 5mm of the orbital rim
   * Not be pedunculated
4. If the subject is a woman of childbearing potential, she has a negative urine pregnancy test and agrees to use an active method of birth control for the duration of the study
5. Subject is non-pregnant and non-lactating
6. Subject is in good general health and free of any known disease state or physical condition which, in the investigator's opinion, might impair evaluation of any Target Lesion or which exposes the subject to an unacceptable risk by study participation
7. Subject is willing and able to follow all study instructions and to attend all study visits
8. Subject is able to comprehend and willing to sign an Informed Consent Form.

Exclusion Criteria:

1. Subject has clinically atypical and - or rapidly growing seborrheic keratosis lesions
2. Subject has presence of multiple eruptive seborrheic keratosis lesions (Sign of Lesser -Trelat)
3. Subject has a current systemic malignancy
4. Subject has used any of the following systemic therapies within the specified period prior to enrollment:

   * Retinoids; 180 days
   * Glucocortico-steroids;
   * Anti-metabolites (e.g., methotrexate);
5. Subject has used any of the following topical therapies within the specified period or in a proximity to any Target Lesion, that in the investigator's opinion interferes with the study medication treatment or the study assessments:

   * LASER, light or other energy based therapy (e.g., intense pulsed light, photo-dynamic therapy;
   * Liquid nitrogen, electrodesiccation, curettage, imiquimod, 5-flurouracil, or ingenol mebutate;
   * Retinoids;
   * Microdermabrasion or superficial chemical peels;
   * Glucocortico-steroids or antibiotics
6. Subject currently has or has had any of the following within the specified period or in a proximity to any Target Lesion that, in the investigator's opinion, interferes with the study medication treatment or the study assessments:

   * A cutaneous malignancy;
   * A sunburn; currently
   * A pre-malignancy (e.g., actinic keratosis); currently
   * Body art (e.g., tattoos, piercing, etc.); currently
   * Excessive tan; currently
7. Subject has a history of sensitivity to any of the ingredients in the study medications
8. Subject has any current skin disease (e.g., psoriasis, atopic dermatitis, eczema, sun damage, etc.), or condition (e.g., sunburn, excessive hair, open wounds) that, in the opinion of the investigator, might put the subject at undue risk by study participation or interfere with the study conduct or evaluations
9. Subject has participated in an investigational drug trial in which administration of an investigational study medication occurred within 30 days prior to enrollment.