Medical History Before Injecting: What Changes the Plan
A medical history before injecting earns its place when an answer changes what you do: treat today, defer or decline. Consensus on preventing filler complications asks about allergies (including to lidocaine), medication such as anticoagulants, immunological disease, herpes, prior infections, active infection or inflammation at the site, previous aesthetic treatments and recent dental work [1].
Several of these questions are about timing rather than permission. Answers about recent illness, dental work, vaccination or a procedure planned for the coming weeks expire quickly, so a form filled in once in the waiting room misses them. Ask them aloud on the day, and treat a blank form as a reason to ask again.
Most forms are filed rather than used
A typical aesthetic form asks about allergies, medication, past illness and pregnancy, and is then filed. It is collected because not collecting it would look bad, which is a legal instinct rather than a clinical one. Filed unread, it changes no decision, although answers on allergies (including to lidocaine), anticoagulant use and bleeding disorders do change the plan [1].
The consensus literature treats the history as crucial to preventing complications, alongside technique and aftercare [1]. Build your questions around the categories above, and ask yourself what each answer would change.
Illness, dental work and vaccination decide when, not whether
A small case series described delayed inflammatory reactions to hyaluronic acid filler soon after COVID-19 vaccination, and one of those patients had reacted once before, after a respiratory infection [3]. Consensus also advises waiting after dental procedures before injecting filler [1]. The proposed mechanisms are hypotheses built to explain small numbers of cases. None of them justifies refusing a patient who was vaccinated last month.
They do justify asking, recording the answer and telling the patient what to expect. A patient who knows that a systemic immune event can occasionally provoke a reaction at an old filler site will phone you rather than panic. They will also arrive with the useful history already gathered.
Herpes simplex is the older, better-established case of the same principle. Antiviral prophylaxis has been studied since the 1990s in laser resurfacing, where patients with a history of cold sores had the highest recurrence rate [4]. Filler consensus reserves prophylaxis for patients with recurrent herpes [1], so the question about cold sores is what decides it.
Fixed waiting rules are worth checking against the evidence
Isotretinoin shows why. Procedures were long deferred for a fixed interval after treatment. A systematic review with consensus recommendations found the evidence for that blanket delay much weaker than its status in practice suggested, particularly for superficial procedures [2].
The authors did not say timing is irrelevant. They said a single interval applied to every procedure was not supported by what had been shown. Some rules you inherit are firmer in textbooks than in the evidence, so find out what each one was built on.
A blank form is a finding, not a clear history
A form with nothing ticked is the commonest result in aesthetic practice and is usually read as a clear history. Often the patient did not count a supplement as a medication or a long-managed condition as a condition, or did not want to write down what they would say aloud.
The fix is not a longer form. Ask two or three of the questions again, aloud, while looking at the person. It takes under a minute and changes the answer often enough to be worth it.
Keep the tone curious, not suspicious. A patient who feels interrogated discloses less. The one who understands that the questions are about getting today right is the one who mentions last week's illness.
Most of this rests on consensus, not trials
Very little of the aesthetic history has been tested as a screening instrument. Most recommendations come from consensus panels reasoning from adverse event reports and neighbouring specialties [1][5]. Nobody has measured what a careful history prevents, so a screening protocol sold with a percentage cut in complications is quoting a figure no study has produced. A careful history is still very likely to help and cannot plausibly harm. Describe it as reasoned standard practice.
Five habits that make the history change decisions
- Ask the timing questions aloud. Recent illness, dental work, vaccination and any procedure planned in the coming weeks. Their answers are short-lived, so a form filed once does not capture them.
- Record deferral and refusal separately. They are different clinical decisions with different follow-up, and a note that blurs them reads badly later.
- Ask about supplements by name. Patients taking fish oil, vitamin E or ginkgo rarely call them medication. If bruising matters to the plan, name them.
- Check where each fixed interval came from. Some are well founded; at least one has been substantially revised [2].
- Write down what you asked. A note that a category was covered and was negative is worth more later than an empty box that could mean anything.
The history rarely appears on a course timetable because it does not photograph well and cannot be demonstrated on a model. When you compare training, ask how much time goes on the patient who should not be treated today, and practise those consultations under supervision.
Read next
- Delayed-Onset Filler Nodules: How to Tell What They Are
- Bruising, Swelling and the First 72 Hours: Aftercare That Works
- Screening for Body Dysmorphic Disorder Before You Treat