What is tacrolimus (topical calcineurin inhibitor) and how should I prescribe/order it (e.g., Protopic®) for a pruritic, desquamating rash on the ears and neck?

What is Tacrolimus and How to Prescribe It

Tacrolimus (Protopic®) is a topical calcineurin inhibitor that you should prescribe as 0.1% ointment applied twice daily to the affected areas of the ears and neck for this pruritic, desquamating rash, particularly if this represents atopic dermatitis or therapy-resistant eczematous dermatitis. 1, 2

What Tacrolimus Is

Tacrolimus is a macrolide immunosuppressant that works by inhibiting calcineurin, which blocks the synthesis of proinflammatory cytokines and downregulates T-cell activity. 3, 4 It is available as an ointment in two strengths:

• 0.03% for children aged 2-15 years
• 0.1% for adults and children ≥16 years 2

The medication has minimal systemic absorption through intact skin and does not cause skin atrophy, unlike topical corticosteroids. 3, 4

How to Prescribe Tacrolimus for Ear and Neck Dermatitis

Prescription Details

• Strength: Tacrolimus 0.1% ointment (for adults/adolescents ≥16 years) 2
• Frequency: Apply twice daily to affected areas 2
• Amount: Thin layer only—use the smallest amount needed to control symptoms 2
• Duration: Short-term or intermittent long-term treatment; stop when symptoms resolve 5, 2

Specific Application Instructions for Patients

• Wash hands before application 2
• Apply thin layer to pruritic, desquamating areas on ears and neck 2
• Do not bathe, shower, or swim immediately after application to avoid washing off the ointment 2
• Wash hands after application (unless treating the hands) 2
• Can apply moisturizers after tacrolimus, not before 2

Evidence for Ear and Neck Use

For chronic external otitis and ear dermatitis specifically, tacrolimus 0.1% has demonstrated 85% improvement rates with significant reduction in pruritus, erythema, edema, and desquamation. 6, 7 In these studies, an ear wick containing 0.1% tacrolimus was changed every 2-3 days for three applications total, with 46% achieving complete remission over 10-22 months. 6

The face and neck are preferred sites for topical calcineurin inhibitors because these areas are more susceptible to corticosteroid side effects like skin atrophy. 8

FDA-Approved Indications and Guidelines

Tacrolimus is FDA-approved for short-term or intermittent long-term treatment of atopic dermatitis in patients ≥2 years who are unresponsive to or intolerant of conventional therapies. 5, 2 The 2023 American Academy of Dermatology guidelines provide a strong recommendation with high certainty evidence for tacrolimus 0.1% and 0.03% ointments in treating atopic dermatitis. 1

Critical Safety Considerations and Contraindications

Black Box Warning

The FDA requires a black box warning regarding theoretical cancer risk, though long-term safety studies show the absolute risk of lymphoma is low and not clinically meaningful. 1, 5 Despite this:

• Do not use continuously for prolonged periods 2
• Only apply to areas with active eczema 2
• Never use in children <2 years old 2

Absolute Contraindications

• Children younger than 2 years 2
• Compromised immune system 5
• Netherton's syndrome (impaired skin barrier leading to systemic absorption) 5, 2
• Active skin infections (bacterial, viral including herpes/chickenpox) 2

Sun Protection Requirements

• Limit sun exposure during treatment 2
• Wear loose-fitting protective clothing over treated areas 2
• Do not use UV light therapy, sun lamps, or tanning beds concurrently 2

When to Reassess

Call for follow-up if: 2

• Symptoms worsen with treatment
• Skin infection develops
• No improvement after 6 weeks of treatment (may indicate alternative diagnosis)

Common Pitfalls to Avoid

• Do not cover with occlusive dressings or bandages—normal clothing is acceptable 2
• Avoid eyes and mouth; do not swallow 2
• Most common side effect is transient burning/stinging at application site, which typically resolves early in treatment 6, 7, 4
• If using moisturizers, apply them after tacrolimus, not before 2

Sample Prescription

Rx: Tacrolimus 0.1% ointment
Disp: 30 grams
Sig: Apply thin layer to affected areas on ears and neck twice daily. Wash hands before and after application. Avoid sun exposure to treated areas. Discontinue when rash resolves or after 6 weeks if no improvement.