Can a patient have an allergic reaction to the Mirena (levonorgestrel), an intrauterine device (IUD)?

Can You Have an Allergic Reaction to Mirena?

Yes, allergic reactions to Mirena (levonorgestrel-releasing intrauterine system) can occur, though they are rare. The FDA drug label explicitly warns not to use levonorgestrel if you have ever had an allergic reaction to it 1. Case reports document acute urticaria and dermatologic reactions following Mirena insertion 2, 3.

Types of Allergic Reactions Documented

Acute systemic reactions:

• Acute urticaria (hives) affecting the entire body with pruritus (itching), occurring within hours of insertion 2
• Associated symptoms may include dizziness and lower abdominal pain 2

Dermatologic reactions:

• Severe seborrhoeic dermatitis has been reported as a side effect, which resolved completely after device removal 3

Clinical Recognition and Management Algorithm

If allergic reaction is suspected:

1. Immediate assessment - Look for urticaria, angioedema, pruritus, respiratory symptoms, blood pressure changes, or widespread rash occurring within hours to days of insertion 2

2. Rule out other causes - The patient in the documented case had no history of allergies to materials used during insertion (plastic, metal, alcohol, medications, povidone-iodine), making the levonorgestrel itself the likely culprit 2

3. Remove the device immediately - In the documented case, prompt removal was recommended and the patient's symptoms resolved without recurrence 2

4. Treat the reaction - Oral corticosteroids (methylprednisolone 10 mg) and antihistamines (desloratadine 5 mg) daily for 5 days successfully treated acute urticaria 2. For dermatologic reactions, topical treatment after removal was effective 3

Important Caveats

Distinguish from infusion/insertion reactions: True allergic reactions persist after stopping exposure and require treatment interventions, unlike simple infusion reactions that resolve quickly 4. Symptoms of true drug allergy include rash, edema, shortness of breath, chest pain, tachycardia, hives/itching, and blood pressure changes 4.

Pre-insertion screening: The FDA label specifically states "Do not use if you have ever had an allergic reaction to levonorgestrel" 1. Always ask about prior exposure to levonorgestrel in any form (emergency contraception, other hormonal contraceptives) before insertion.

Not related to copper allergy: For patients concerned about metal allergies, note that Mirena contains levonorgestrel (a hormone), not copper. Copper allergy is relevant only for copper IUDs, and even then, studies found no correlation between copper allergy and IUD side effects 5.

When to Suspect Levonorgestrel Allergy vs. Other Causes

Favor allergic reaction if:

• Symptoms appear within hours to days of insertion 2
• Urticaria, angioedema, or severe dermatitis develops 2, 3
• No other explanation exists (infection, trauma, other medications) 2
• Symptoms resolve after device removal 2, 3

Consider alternative diagnoses:

• Pelvic infection (occurs in first 20-21 days post-insertion per CDC guidelines) 6
• Normal side effects like menstrual changes, headache, breast pain, nausea, or abdominal pain (common, not allergic) 1
• Vasovagal reaction during insertion (immediate, self-limited)