Zest Health Guide to Topical Calcineurin Inhibitors (TCIs)

If your rash keeps coming back in the same sensitive spots, like around your eyes, on your neck, or in skin folds, you know how frustrating that can be. Steroids can help, but they are not always the right tool for delicate areas. That is where topical calcineurin inhibitors, or TCIs, come in.

TCIs calm the immune response in your skin without the side effects that can come from long-term steroid use. This guide explains how they work, how to use them, and what the research really says about safety.

What Are Topical Calcineurin Inhibitors?

TCIs are prescription creams and ointments that treat eczema, psoriasis, and other rashes, especially in areas where other medications can be too harsh. They work by calming the immune signals that cause itching, redness, and swelling.

Because they are not steroids, TCIs do not thin the skin over time. That makes them especially well-suited for the face, neck, groin, and skin folds. They are often described as a steroid-sparing option.

TCIs are available as two medications: Protopic (tacrolimus) ointment and Elidel (pimecrolimus) cream. Your Zest provider will recommend the one that fits your skin and condition.

How to Apply Your Medication

1. Wash your hands before applying.
2. Apply a thin layer to the affected area only.
3. Gently rub in until absorbed.
4. Wash your hands after applying, unless you are treating your hands.
5. Use once or twice daily as directed by your provider.

How Much to Use

A helpful way to measure your medication is the Fingertip Unit, or FTU. This is the amount of cream squeezed from the tip of your finger to the first crease. One FTU covers roughly the front and back of one adult hand.

For smaller areas, use less. Your provider can help you get the right amount for your specific areas.

How Long Does Treatment Last?

Treatment length depends on your symptoms and where your rash is. Common patterns include:

• During a flare. Use as directed until your skin improves.
• Maintenance. Some people use TCIs a few times per week to help prevent future flares.

Even if your skin looks better, keep following your provider's plan. Stopping too early can cause your rash to return. TCIs are designed for safe, long-term use.

Getting Started

Your Zest provider will determine if TCIs are right for you based on your skin condition, where your rash is located, and the severity of your symptoms. Before starting, submit baseline photos of your skin for a severity assessment. No routine blood work is needed, but share all current and past medications with your provider.

What to Expect

• Itching may improve within a few days.
• Redness and irritation often improve within 1 to 2 weeks.
• Sensitive areas like the face or skin folds may improve even faster.

Safety and Side Effects

TCIs are prescribed regularly by dermatology providers and are considered safe when used as prescribed. Most side effects are mild and can include:

• Burning or stinging, especially when first starting
• Itching
• Increased sensitivity to heat or cold in the treated area
• Increased sun sensitivity. Use sunscreen on treated areas when going outdoors.

Less common effects include flu-like symptoms or folliculitis, which means small red bumps near hair follicles.

A Note on the Black Box Warning:

You might see a warning on your packaging about a possible risk of lymphoma or skin cancer. We understand that can feel alarming, and we want to give you the full picture.

• The warning is based on theoretical risk, not proven harm from topical use.
• It comes from animal studies using very high doses, and from patients taking oral or injectable immune-suppressing medicines. Those are very different from topical, skin-only treatments.
• Large studies in people using these creams have not shown a clear increase in cancer risk when used as directed.

If you have questions or concerns about this, please bring them up with your Zest provider. 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 

Reach out if you notice any of the following:

• No improvement after 6 weeks of treatment
• Signs of a severe allergic reaction or infection
• Unusual worsening redness, pain, or swelling, or other signs of skin infection (pus, warmth, fever)
• Any vision changes if using medication near your eyes

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.