Klisyri Side Effects: What to Expect and When to Call Your Doctor

Before starting Klisyri (tirbanibulin) for actinic keratosis, most patients want to know: what will my skin look like? Will it hurt? What's considered normal versus a sign that something is wrong? This guide breaks down everything you need to know about Klisyri's side effect profile — based on the clinical trial data and FDA prescribing information.

Are Skin Reactions Normal With Klisyri?

Yes. Skin reactions at the application site are expected with Klisyri — they are actually a sign the drug is working on the precancerous skin cells. In clinical trials, a large majority of patients experienced local skin reactions:

91% of patients experienced erythema (redness)

82% experienced flaking or scaling of the skin

9% reported application site pruritus (itching)

10% reported application site pain

These reactions are typically confined to the area where Klisyri was applied. The good news: because Klisyri is only applied for 5 consecutive days, the skin reaction period is significantly shorter than with other AK treatments like fluorouracil (which requires 2–4 weeks of application and a longer healing period).

Common Side Effects (Mild to Moderate)

The following side effects are reported in 2% or more of patients and are expected:

Erythema (redness): The treated skin will appear red during and after the 5-day application. This begins during treatment and typically peaks about 8 days after starting.

Flaking/scaling: Skin peeling and flaking in the treated area is common and expected — it reflects the shedding of damaged skin cells.

Crusting: Some patients develop a crust over the treated area as it heals.

Pruritus (itching): Mild to moderate itching at the application site is common.

Application site pain: Some patients experience stinging or burning during or after application.

Serious Side Effects: When to Call Your Doctor

While most side effects are mild and limited to the treatment area, some reactions warrant prompt medical attention:

Vesiculation or pustulation: Blistering or pus-filled bumps in the treated area. Mild cases (7% in trials) may be expected, but severe cases require medical evaluation.

Erosion or ulceration: Open sores in the treated skin (mild: 9%, moderate: 3% in trials). If erosion is severe or spreading, contact your provider.

Swelling: Significant swelling (edema) in the treatment area should be reported to your doctor.

Eye irritation: If Klisyri accidentally gets in or near your eyes, immediately flush with water and seek medical care. The drug can cause serious eye irritation.

Allergic reaction: Signs of a serious allergic reaction (hives, difficulty breathing, facial swelling) require immediate emergency care.

How Long Do Klisyri Side Effects Last?

Studies show that areas of actinic keratosis treated with Klisyri can start to look better about 8 days after starting treatment. Side effects like redness and flaking typically peak around that time and begin improving within 2 weeks. Most side effects resolve within approximately 4 weeks of completing the 5-day course.

Tips to Manage Klisyri Side Effects

Do NOT cover the treatment area with a dressing — occlusion increases irritation risk

Do NOT use topical corticosteroids (hydrocortisone cream) on the treated area — steroids may interfere with Klisyri's mechanism

Do NOT wash the area for at least 8 hours after each application

Protect treated skin from sun exposure — use broad-spectrum sunscreen daily

Cool compresses can help relieve itching and discomfort between applications

Ask your dermatologist about safe moisturizers to use during healing after the 5-day course

For a full overview of Klisyri's uses and how it works, see our guide: What Is Klisyri? Uses, Dosage, and What You Need to Know in 2026.