Psoriasis and the Koebner Phenomenon: Needle-Induced Lesions

A patient with psoriasis asks whether she can have botulinum toxin in her forehead. She shows an old plaque on her elbow and a milder one on her scalp, and says that "when I get hurt, the patch shows up in the same spot." Without knowing it, she described the Koebner phenomenon, which is exactly what makes this patient profile a special topic in orofacial harmonization (HOF). This guide explains the concept, points out what to assess and how to talk about it, at a review level. The decision to treat, the timing, and the technique belong to the qualified professional, preferably in dialogue with the physician who follows the patient, according to their professional council's rules.

What is psoriasis, in practical terms?

Psoriasis is a chronic inflammatory skin disease with multiple causes and an immune component. It is characterized by reddened, scaly plaques that can appear anywhere on the body, with a preference for the elbows, knees, scalp, and sacral area. The course alternates between active phases and remission, and treatment involves specialist follow-up, sometimes with medications that modulate immunity.

For the HOF professional, three aspects matter:

1. The patient's skin has an inflammatory tendency. Any trauma may trigger an exaggerated response.
2. The medications used can alter healing and infection risk. The medical history should ask about them.
3. The disease has an emotional impact. Many patients live with prejudice and insecurity, which calls for a careful approach.

What is the Koebner phenomenon?

The Koebner (or isomorphic) phenomenon describes the appearance of lesions typical of a skin disease in areas with no prior lesion that suffered trauma. In psoriasis it is well described, and the trauma can be mechanical (scratching, friction, pressure), thermal (sunburn), chemical, or the result of procedures such as biopsies, tattoos, and injections.

In the HOF office, the reasoning is straightforward: every puncture is a miniature trauma. A needle, a cannula, microneedling, a peel, or a laser can, in theory, be a trigger. It does not mean this happens in every patient, and the frequency varies, but it is a possibility worth discussing beforehand.

How does the risk change by procedure?

This table is a guide to reasoning, not a rule. The final decision depends on the area, the disease phase, and the individual history.

What to ask in the medical history?

For the context of autoimmune diseases in general, see autoimmune diseases and fillers. For the reasoning on medications that affect healing, systemic corticosteroids and healing in HOF.

When to postpone the procedure?

Some situations call for waiting:

• Psoriasis in an active phase, with new lesions appearing or progressing.
• A lesion in the area to be treated or very close to it.
• Active infection, such as candidiasis, impetigo, or herpes.
• Recent medication change, which can alter the skin's behavior.
• Fever or acute illness.
• Patient going through emotional decompensation, with worsening skin condition.

Postponing is a legitimate approach and should be recorded with the reason.

How to counsel the patient?

The conversation needs to be clear, without alarmism and without minimizing. The patient with psoriasis knows their own skin's behavior well and often has valuable observations. It is worth listening.

If the patient has a dermatologist, contacting them beforehand helps. It is worth sending a short summary of the plan and asking for the physician's assessment, with the patient's consent.

How to follow up afterward?

Schedule a follow-up and ask the patient to watch for changes at the treated points.

If a new lesion appears at the injection points, photograph it and refer to the dermatologist. Do not treat on your own a lesion whose diagnosis belongs to the specialist. To tell it apart from infection, see facial cellulitis after a procedure.

Are there specific technique precautions?

At an overview level, some principles help:

1. Prefer the fewest punctures that achieve the goal, without compromising the quality of the result.
2. Respect aseptic technique, because the skin barrier is altered and infection risk is higher.
3. Avoid injecting over or very close to plaques.
4. Handle the skin gently, avoiding friction and rubbing afterward.
5. Consider starting with a small area and watching the response before expanding the plan.
6. Avoid agents that cause extensive inflammation when they are not essential.

And the emotional impact?

Psoriasis is often accompanied by psychological distress, and the search for HOF may be tied to self-esteem. This calls for empathy and care so the procedure does not become an expectation of "fixing" the disease. Harmonization does not treat psoriasis, and it is important that the patient knows this. If you notice intense distress, refer them to appropriate support.

What should be recorded?

In the patient record, record: reported diagnosis, phase, medications, location of lesions, pre-procedure photos, the Koebner discussion, the decision made, instructions, and follow-up. The informed consent should mention the possibility of a needle-induced lesion. If the patient declined the suggestion of contacting the dermatologist, note it.

In summary

Psoriasis does not rule out harmonization, but it calls for more conversation and more care. The Koebner phenomenon is a real possibility, and the way forward is to assess the disease phase, choose areas and techniques cautiously, coordinate with the specialist, counsel the patient, follow up closely, and document. When in doubt, postponing is an acceptable approach.