I have itching at the Nexplanon (etonogestrel) implant insertion site placed recently; how should I manage it and when is it concerning?

Management of Itching at Nexplanon Insertion Site

Most itching at the Nexplanon insertion site is a benign local reaction that resolves with symptomatic treatment (oral antihistamines, cold compresses, topical corticosteroids), but you must rule out infection and consider rare allergic reactions to the implant components if symptoms persist or worsen beyond 7-10 days. 1, 2, 3

Initial Assessment and Differential Diagnosis

When evaluating insertion site itching, systematically distinguish between three key categories:

Benign Local Reactions (Most Common)

• Redness, swelling, itching, and mild pain are expected local reactions that typically increase in size for 24-48 hours post-insertion and resolve within 5-10 days 1
• These reactions are usually self-limited and require only symptomatic management 1

Infectious Complications (Must Rule Out)

• Look specifically for progressive swelling, warmth, purulent drainage, fever, or lymphangitis extending beyond the insertion site 1, 3
• Infection at the implant site is rare but represents a serious complication requiring prompt intervention 1, 3
• The French pharmacovigilance data showed infectious complications were among the infrequent but serious adverse events requiring attention 4

Allergic Reactions (Rare but Important)

• True allergic reactions to Nexplanon components (barium sulfate or ethylene vinyl acetate copolymer) are extremely rare but have been documented 2, 3
• Allergic reactions may present with persistent itching, urticaria, or angioedema not contiguous with the insertion site 1, 2
• Unlike local reactions, allergic symptoms persist or worsen beyond 7-10 days and may require implant removal for resolution 2, 3

Immediate Management Algorithm

For Mild Local Reactions (No Signs of Infection or Allergy)

Apply symptomatic treatment immediately:

• Cold compresses to reduce local pain and swelling 1
• Oral antihistamines to reduce itching and cutaneous reactions 1
• Oral analgesics for pain management 1
• Topical corticosteroids may be considered, though definitive proof of efficacy is lacking 1

Antibiotics are NOT indicated unless there is clear evidence of secondary infection, as swelling and inflammation are caused by mediator release, not infection 1

For Suspected Infection

• Examine for progressive warmth, purulent drainage, fever, or lymphangitis 1, 3
• If infection is confirmed, initiate appropriate antibiotics and consider implant removal if the infection does not respond to medical treatment 3
• Hematoma or seroma at the site increases infection risk and should be monitored closely 1

For Suspected Allergic Reaction

• If symptoms persist beyond 7-10 days or worsen despite symptomatic treatment, consider true allergic reaction 2, 3
• Allergic reactions to barium sulfate (the radiopaque component) have been reported, though extremely rare 2
• Medical treatment alone is typically insufficient; implant removal is required for symptom resolution 2
• In documented cases, symptoms resolved within 72 hours after implant removal 2

When to Worry: Red Flags Requiring Urgent Evaluation

Seek immediate evaluation if any of the following develop:

• Systemic symptoms: fever, chills, or malaise suggesting infection 1, 3
• Progressive swelling extending beyond 10 cm or worsening after 48 hours 1
• Signs of deep infection: fluctuance, purulent drainage, or lymphangitis 1, 3
• Respiratory symptoms, bronchospasm, or hypotension suggesting anaphylaxis 1
• Persistent or worsening symptoms beyond 7-10 days despite appropriate symptomatic treatment 2, 3

Evidence-Based Context and Reassurance

• The NORA study (largest prospective evaluation with 7,364 insertions) demonstrated that procedure-related complications are rare when performed by trained clinicians 5
• The most common patient-reported event was "pins and needles/numbness in the arm/hand/fingers," not persistent itching 5
• Skin reactions were reported in only 524 cases out of thousands in French pharmacovigilance data, confirming their relative rarity 4
• Serious adverse events occurred in only 7% of all reported cases, with most being non-serious local reactions 4

Common Pitfalls to Avoid

• Do not prescribe antibiotics for simple local reactions without evidence of infection, as this promotes antibiotic resistance and does not address mediator-driven inflammation 1
• Do not dismiss persistent symptoms beyond 7-10 days as normal healing; this may indicate allergic reaction requiring implant removal 2, 3
• Do not aspirate hematomas with needles, as this introduces skin flora and increases infection risk 1
• Do not delay removal if true infection or allergy is confirmed, as medical management alone is often insufficient 2, 3