Zest Health Guide to Topical Janus kinase (JAK) Inhibitors

If you have eczema, you know the itch. It can be relentless, distracting, and exhausting. If you have vitiligo, you may have watched patches of color slowly fade and wondered if anything could bring it back. Topical JAK inhibitors are a newer class of medication that targets both of these concerns in a different way than steroids or older creams.

This guide explains how they work, how to use them, and what to realistically expect.

What Are Topical JAK Inhibitors?

JAK stands for Janus kinase. JAK enzymes are proteins in your body that send signals telling your immune system to create inflammation. Topical JAK inhibitors block those signals. When the signals are turned off, itching, redness, and rash can calm down quickly.

There are currently two topical JAK inhibitors available:

• Opzelura (ruxolitinib). Used for atopic dermatitis, also called eczema, and nonsegmental vitiligo. FDA-approved for people 12 and older for vitiligo, and 2 and older for eczema.
• Anzupgo (delgocitinib). Used specifically for moderate to severe chronic hand eczema in adults 18 and older.

Your Zest provider will determine which one is right for you based on your diagnosis and where your symptoms are.

What Makes These Different

Topical JAK inhibitors are not steroids. They do not cause skin thinning or stretch marks, even with longer use. That makes them a strong option for sensitive areas, including the face and eyelids.

Because the medication is applied to the skin rather than taken by mouth, it stays local. The risks linked to oral JAK inhibitor pills are much lower with the topical form.

Before You Begin

A few important things to know before starting:

• Active infections. Because JAK inhibitors work on the immune system, they should not be used if you have an active, serious infection. Talk to your provider if you are unsure.
• Vaccines. Make sure you are up to date on vaccines, including shingles, before starting. Avoid live vaccines while using these medications.
• Medications. Share all current and past medications with your provider before starting.

How to Apply Your Medication

Application is slightly different depending on which medication you are using.

• Opzelura. Can be applied to affected areas on the body and face, including sensitive skin around the eyes, mouth, and groin. Do not apply inside the eyes, mouth, or vagina.
• Anzupgo. Applied specifically to affected areas on the hands and wrists.

Follow these steps for both:

1. Apply a thin layer to affected areas twice daily.
2. Wash your hands after applying, unless your hands are the area being treated.
3. Try pairing your application with a daily habit, like brushing your teeth, to help you stay consistent.

For Opzelura, do not use more than one 60g tube per week. For Anzupgo, do not exceed 30g per 2 weeks.

How Much to Use

We recommend using the Fingertip Unit (FTU) when you are getting started:

• This is the amount of cream squeezed from the tip of your finger to the first crease.
• 1 FTU covers about the size of the front and back of one adult hand.

A few things to keep in mind as you get started:

• If you're treating a small spot, use less, you don't need a full FTU for every area
• For eczema, apply only to areas that need it, keeping total coverage to no more than 20% of your body surface area
• For vitiligo, limit coverage to 10% of your body surface area

Every person's skin is different, and different body parts need different amounts. Your Zest provider can walk you through exactly how much to use and where.

Getting Started

• Submit baseline photos of your skin condition for a severity assessment
• No routine blood work is needed, but please share all current and past medications with your provider
• Provide previous treatment records, if requested

What to Expect

• Itch relief. Many people feel a significant reduction in itching within days, and sometimes even within hours of the first use.
• Eczema clearing. Treatments are often used as needed until symptoms resolve.
• Vitiligo repigmentation. Repigmentation takes longer, often 6 or more months of consistent use to see meaningful results. Progress is real even when it feels gradual.

Safety and Side Effects

Topical JAK inhibitors deliver medication directly to the skin, which helps limit side effects. Most people experience only mild effects.

Common effects include:

• Acne or redness at the application site
• Mild cold symptoms
• Headaches

Rare but serious effects to watch for include:

• Serious infections
• Blood clots
• Blood count changes

Contact your provider right away if you notice fever, leg swelling or pain, or shortness of breath.

A Note on the Black Box Warning

You may see a black box warning on your packaging. This warning exists because oral JAK inhibitor pills have been linked to more serious risks in some people.

This topical medication is different. It stays on the skin and does not enter your body the way a pill does. The risks are much lower. The warning is included out of caution, not because topical use carries the same level of risk.

If you have questions about this, bring them to your next visit. We are always here to talk it through with you

Storing Your Medication

• Store at room temperature
• Keep tube or bottle tightly closed
• Keep out of reach of children
• Do not ingest medication
• Check expiration date before each use

When to Contact Your Zest Team 

• No improvement after 8 weeks for eczema, or 24 weeks for vitiligo 
• Signs of a severe allergic reaction or infection
• Unusual worsening redness, pain, or swelling, or signs of skin infection (pus, warmth, fever)
• Fever, leg swelling, shortness of breath, or any other new or concerning symptom

Have more questions? Contact your Zest care team by texting (865) 426-1746 or sending a message from your portal. You've got this, and we've got you.