A Study of Tirbanibulin Ointment and Diclofenac Sodium Gel for the Treatment of Adult Participants With Actinic Keratosis on the Face or Scalp

Inclusion Criteria: * A treatment field (TF) on the face or scalp (excluding lips, eyelids, ears, and inside the nostrils), that: a) is a contiguous area measuring 25 cm\^2, b) contains 2 to 8 clinically typical, visible, and discrete actinic keratosis (AK) lesions, and c) has an overall clinical picture that is consistent with Olsen grade 1 * If a women of child-bearing potential (WOCBP), that is, fertile, defined as a female in the life period from menarche and until becoming post-menopausal (no menses for 12 months without an alternative medical cause) or permanently sterile (with hysterectomy, bilateral salpingectomy or bilateral oophorectomy at least 3 months prior to Screening), she must: a) Have a negative urine pregnancy test using a highly sensitive method at screening and on Day 1 prior to treatment administration. b) Be using effective methods of birth control. c) Agree to have pregnancy tests while in the study and at the end of the study * Participants should be willing to avoid sunlight or ultraviolet (UV) light exposure, including the use of tanning beds, to the face or scalp during the study * Participants should have the ability to understand the purpose and risks of the study, willingness and ability to comply with the protocol, and provide written informed consent in accordance with institutional and regulatory guidelines Exclusion Criteria: * The location of the TF is: a) on any location other than the face or scalp. b) within 5 centimeters (cm) of an incompletely healed wound. c) Within 10 cm of a suspected basal cell carcinoma (BCC) or other neoplasm. d) on the lips, eyelids, ears, or inside the nostrils, periorbital, perioral, or the skin surrounding the nostrils * Presence in the TF of: a) clinically atypical and/or rapidly changing AK lesions b) hyperkeratotic or hypertrophic lesions, recalcitrant disease (had cryosurgery on 2 previous occasions), and/or cutaneous horn. c) confluent AK lesions (that is, non-discrete lesions, as per inclusion criterion 2). d) Persisting AK lesions at the screening visit following topical treatment with diclofenac sodium 3 percent (%) gel * History of any malignant skin tumour in the TF or history of skin tumour in any region of the body which has metastasized or in which metastasis within the study period is likely * History of any malignant tumour with systemic antitumor treatment (including radiotherapy) within 12 weeks prior to the Screening Visit or systemic antitumor treatment is expected while on the study * Immunocompromised participants, including participants with a history of chronic systemic lymphoma or chronic myeloid leukaemia, or organ transplant recipients