Epidermal growth factor receptor inhibitors (EGFRIs) are widely used targeted agents that have been approved for the treatment of various tumor types. In some clinical studies with EGFRIs, the incidence of dermatology AE, the skin rash, is reportedly as high as 95%, which profoundly impact the patients' quality of life. However no treament for onset skin rash has been approved to be effective by any clinical trial yet. Janus kinase (JAK) inhibitor, has been approved for or studied in a variety of skin conditions such as alopecia areata, atopic dermatitis, and psoriasis. Thus the investigators intend to evaluate the efficacy and safety of JAK inhibitor cream for the treatment of EGFRIs-induced skin rash in cancer patients.

Inclusion Criteria:

• 18 years of age or older.
• Pathologically confirmed cancer receiving EGFRI-based therapy (monotherapy or as part of a combination therapy regimen).
• Skin rash causally related to EGFRI therapy of grade 1 or higher (according to MESTT criteria).
• ECOG performance score < 2.
• Able to use topical medications and complete questionnaires reliably with or without assistance.
• Life expectancy of greater than 6 months.
• Ability to understand and the willingness to sign a written informed consent.

Exclusion Criteria:

• Use of any other topical medications in the treatment areas (face) within 7 days prior to randomization or duing the study.
• Use of Tetracycline (e.g. minocycline, doxycycline) within 14 days prior to randomization or duing the study.
• Use of other cancer medications known to result in skin rash in the face or upper chest/upper back area within 4 weeks prior to randomization or duing the study.
• Known hypersentitivity to JAK inhibitors.
• With other skin disorders that may affect efficacy evaluation, including but not limited to: eczema, psoriasis, etc.
• Uncontrolled intercurrent illness.
• Significantly abnormal lab test.
• Pregnant or nursing women.