Safety and Efficacy of ARQ-154 Foam in Subjects With Seborrheic Dermatitis

Inclusion Criteria: 1. Participants legally competent to sign and give informed consent. 2. Males and females ages 18 years and older (inclusive) at the time of consent. 3. Clinical diagnosis of seborrheic dermatitis of at least 3 months duration as determined by the Investigator. Stable disease for the past 4 weeks. 4. Seborrheic dermatitis of the scalp and/or face and/or trunk and/or intertriginous areas. 5. An Investigator Global Assessment (IGA) of disease severity of at least Moderate ('3') at Baseline. 6. Overall Assessment of Erythema and Overall Assessment of Scaling scores of at least Moderate ('2') at Baseline. 7. Females of childbearing potential (FOCBP) must have a negative serum pregnancy test at Screening (Visit 1) and a negative urine pregnancy test at Baseline (Visit 2). 8. Females of non-childbearing potential must either be post-menopausal with spontaneous amenorrhea for at least 12 months or have undergone surgical sterilization. 9. Subjects in good health as judged by the Investigator, based on medical history, physical examination, vital signs, serum chemistry labs, hematology values, and urinalysis. 10. Subjects are considered reliable and capable of adhering to the Protocol and visit schedule according to the Investigator judgment. Exclusion Criteria: 1. Subjects who cannot discontinue treatment with therapies for the treatment of seborrheic dermatitis prior to the Baseline visit and during the study according to Excluded Medications and Treatments. 2. Planned excessive exposure of treated area(s) to either natural or artificial sunlight, tanning bed or other LED. 3. Subjects who cannot discontinue the use of strong P-450 cytochrome inhibitors e.g., indinavir, nelfinavir, ritonavir, clarithromycin, itraconazole, ketoconazole, nefazodone, saquinavir, suboxone and telithromycin for two weeks prior to the Baseline visit (Visit 2) and during the study. 4. Subjects who cannot discontinue the use of strong P-450 cytochrome inducers e.g., efavirenz, nevirapine, glucocorticoids, barbiturates (including phenobarbital), phenytoin, rifampin, and carbamazepine for two weeks prior to the Baseline visit (Visit 2) and during the study. 5. Subjects with PHQ-8 ≥10 at Screening or Baseline visits. 6. Previous treatment with ARQ-151 and ARQ-154. 7. Subjects who have received oral roflumilast (Daliresp®, Daxas®) or other PDE-4 inhibitors (apremilast) within the past 4 weeks. 8. Known allergies to excipients in ARQ-154 foam. 9. Known or suspected: severe renal insufficiency or moderate to severe hepatic disorders; hypersensitivity to component(s) of the investigational products; or history of severe depression, suicidal ideation, or Baseline/Screening C-SSRS indicative of suicidal ideation, whether lifetime or recent/current. 10. Subjects with a history of a major surgery within 8 weeks prior to Baseline (Visit 2) or has a major surgery planned during the study. 11. Subjects with any condition on the treatment area which, in the opinion of the Investigator, could confound efficacy measurements. 12. Subjects unable to apply product to the scalp due to physical limitations. 13. Females who are pregnant, wishing to become pregnant during the study, or are breast-feeding. 14. A clinically relevant history of abuse of alcohol or other drugs, at the discretion of the Investigator. 15. Subjects who are unable to communicate, read or understand the local language, or who display another condition, which in the Investigator's opinion, makes them unsuitable for clinical study participation. 16. Subjects who are family members of the clinical study site, clinical study staff, or sponsor, or family members of enrolled subjects. 17. Any condition that in the Investigator's assessment would preclude the subject from participating in the study.