Botulinum toxin for nasal lines (bunny lines)

Nasal lines, known by the English name "bunny lines", are the oblique wrinkles that appear on the sides of the nasal bridge when the patient smiles, frowns or scrunches the nose. They are dynamic wrinkles, tied to muscle contraction, and so a frequent indication for botulinum toxin. The area is small, but its proximity to the muscles that raise the lip makes planning less simple than it seems.

This guide is a review: functional anatomy, assessment, risks and expectations. It gives no doses, points or depth, which are the decision of the qualified professional, following the product label and the rules of their professional council in Brazil.

Which muscles form the nasal lines?

The complete map, with elevators and depressors, is in facial muscles in botulinum toxin. The anatomy of the nose, including its vascularization, is in the nose area.

Why do nasal lines appear after glabella treatment?

It is a common complaint at follow-up: "the forehead lines are gone, but now they show up on my nose". After treating the glabella and the periorbital region, some patients start recruiting the nose muscles more when frowning or smiling. The literature describes this recruitment as a compensatory effect.

In some cases, the lines were already there and became more visible because the rest of the expression decreased. In others, the contraction pattern really did change. The difference matters for the conversation: it is not a "side effect" of the first treatment, but a feature of that patient's muscle pattern.

How to assess the patient?

1. Dynamic expressions: wide smile, frown, nose scrunch and tightly closed eyes.
2. Distribution of the lines: only on the lateral bridge, extending to the inner corner of the eye, or running down toward the nostril wing and the lip.
3. Symmetry: note whether the lines are more marked on one side. See facial asymmetry.
4. Smile and upper lip: observe gingival display and lip elevation. Patients with a long upper lip or little tooth display have less margin for any drop.
5. Previous treatments: date, area and product of the last toxin, and whether the lines appeared afterward.
6. Static wrinkles: if the line persists at rest, the toxin reduces contraction but does not completely erase the crease.

Is the area on the label?

Each type A botulinum toxin registered with ANVISA (Brazil's health regulatory agency) has its own approved indications, listed on the label. Approved aesthetic indications tend to focus on glabellar lines and, for some products, forehead and periorbital lines. Treating nasal lines may be off-label use, depending on the product. Check the label of the product you use and record it in the consent when applicable. The differences between products are in type A botulinum toxins: what changes between products, and units are not interchangeable between brands (see toxin unit).

What are the risks in nasal lines?

• Drooping or lengthening of the upper lip, if the toxin reaches the lip elevators.
• Smile asymmetry, by the same mechanism, on one side only.
• Asymmetry of the lines themselves, from a difference in response between sides.
• Bruising and swelling at the injection point, in a well-vascularized area.
• Incomplete result, when part of the lines come from untreated muscles.
• Compensatory effect in another area, as happens in the opposite direction.

What to expect after the injection?

Timelines vary with the product, the dose and the patient. Questions about this, in patient language, are in how long the toxin takes to work and how long the toxin lasts.

Which nasal line patterns show up in the consultation?

Not every line on the nose has the same origin, and separating the patterns helps decide whether the toxin makes sense:

What are the most common mistakes?

• Treating nasal lines in isolation without looking at the glabella and the periorbital region, which are often part of the same pattern.
• Not assessing the smile beforehand. The complaint of a drooping lip at follow-up comes from an assessment that did not look at the lip.
• Correcting aggressively at follow-up. A small adjustment is usually enough; adding too much raises the risk in neighboring muscles.
• Not warning that the area may be off the label of the product used.
• Promising the lines will disappear, when some of them are already static.

How to explain it to the patient?

Use an informed consent that mentions the temporary change in the smile and, when applicable, off-label use. There is an informed consent template for botulinum toxin and one for post-toxin instructions.

And in Harmy?

Checklist before toxin in nasal lines

1. Dynamic expressions photographed: smile, frown and nose scrunch.
2. Lines present before earlier treatments, or that appeared afterward, recorded.
3. Smile, gingival display and upper lip length assessed.
4. Indication checked on the product label; off-label use disclosed when applicable.
5. Patient informed about the risk of a temporary change in the smile.
6. Product, lot and units per area in the patient record; follow-up scheduled.