PRP Hair Treatment Side Effects and Aftercare: What's Normal and What Isn't

Most of what happens after a PRP scalp session is small and short: a sore, tender scalp, some redness or swelling, sometimes a headache, usually gone within a day or two. That is what the published reviews and a university hospital's own patient page describe. Read on for the few reactions that are not small, the people who should not be injected at all, and how loosely the word “aftercare” is used by the clinics selling the sessions.

Each section names its sources, all of them read on 18 October 2026. None of it is an instruction: the written sheet from the clinician who injects you outranks every line on this page, and a doctor who knows your medicines outranks the sheet.

Signs to call the clinic, or get urgent care, today

Ordinary soreness fades. These do not fit the ordinary pattern, and each one is a reason to phone the injecting clinic the same day, or to seek urgent care if the clinic cannot be reached:

• Pain, redness or swelling that grows after the first day instead of settling, or skin that turns hot, or a scalp that starts to weep or crust. A 2023 case report notes that the published list of PRP side effects, short as it is, includes infection.
• Fever, chills or feeling unwell after the session.
• A painful rash, blisters, or swelling spreading towards the forehead or an eye. Two published case reports describe shingles affecting the eye (herpes zoster ophthalmicus) after PRP for pattern hair loss; in the 2025 report it was first treated as an allergy and as bacterial cellulitis, and only after it worsened was it confirmed and treated with intravenous antivirals and antibiotics.
• Tender, swollen lumps in the neck. A 2019 case report describes acute, painful lymph-node swelling shortly after PRP delivered with a microneedling pen.
• Any change in vision or eye pain. That is never a scalp-tenderness problem.

None of these is common, and the reports describe single patients. They are listed first because the cost of recognising them late is much higher than the cost of a phone call.

What the reviews actually reported

PRP for hair has dozens of small trials and several pooled analyses, and their safety findings point the same way: discomfort during injection is the dominant complaint, and serious harm is rarely reported. The detail matters more than the summary, because each review counted something slightly different.

Two things stand out. First, the trials were not designed to find rare problems. A meta-analysis of a few hundred people can show that common side effects are similar between groups; it cannot show that an uncommon complication never happens, and the case reports are the reminder. Second, “PRP” is not one product. The 2025 meta-analysis found that whether the platelets were activated before injection changed how often side effects were reported, which is a preparation detail most patients never hear about.

Who is usually told not to have PRP

Because PRP is your own blood, it is tempting to assume anyone can have it. The 2022 review lists the opposite. Its absolute contraindications are a critically low platelet count, a platelet-function disorder, unstable circulation, sepsis, and infection at the injection site. Its relative contraindications, the ones that call for a conversation rather than an automatic no, include anti-inflammatory painkillers in the previous 48 hours, a steroid injection at the site within a month, steroid tablets within two weeks, a recent illness or fever, cancer (bone and blood cancers especially), anaemia, a low platelet count and smoking.

The review does not name blood thinners or antiplatelet medicines, yet they are exactly the kind of thing a clinic sheet tends to mention in passing. Never stop or pause a prescribed anticoagulant, antiplatelet or aspirin because a cosmetic clinic's leaflet suggests it. That decision belongs to whoever prescribed it, and for some people the risk of stopping is far larger than any benefit to hair. If the medicine cannot be paused, the honest answer may be that PRP is not for you.

The other screening question is diagnosis. PRP studies mostly enrolled pattern hair loss. A scalp with an undiagnosed rash, scarring alopecia or active infection is a dermatology question first, which is the order the PRP explainer on this site argues for as well.

The first 48 hours: what published sheets say

There is no single standard aftercare protocol for PRP on the scalp, and the sheets disagree on details. Here are two read the same day, side by side, so you can see where they differ and bring the difference to your own clinic.

The point of the table is not to pick a winner. It is that “can I wash my hair tonight?” has two different published answers from two credible places, and the correct one for you is whichever your own injector wrote down, because it was written for their preparation and their technique. If you were given nothing in writing, that is itself worth noticing.

Exercise, washing, sun and colouring

People ask about these because the day after a session is a normal day for most of them. The pattern across the two sheets is consistent even where the hours differ: a short pause on heat, sweat and swimming, a short pause on chemical hair treatments, and a gentle approach to the scalp for a day or two. The reasoning given is about healing injection sites and avoiding irritation, not about protecting the result, and neither page claims that following it changes how well PRP works.

If you colour or bleach your hair, ask the clinic how long they want you to wait and get it in writing; the Zurich page says “a few days” without a number. If you train hard, ask whether a walk counts as exercise under their sheet. These are small questions, and a clinic that cannot answer them clearly is telling you something about how the rest of the appointment will go.

Shedding after PRP

Some clinic pages say hair can shed in the weeks after a session. This reading did not find that measured in the reviews above, so the site will not state it as a known effect or give it a timeline. What is true in general is that hair-cycle changes after a scalp procedure are worth showing to a dermatologist rather than interpreting alone, and that a clinic which tells you to expect shedding should also tell you what they would count as abnormal.

Questions about the kit and who injects

Several of the risks above come back to two variables the patient rarely sees: how the PRP was prepared, and who holds the needle. Worth asking before anyone draws blood:

1. Which preparation system do you use, and is the platelet sample activated before injection? The 2025 meta-analysis linked non-activated PRP to more reported side effects.
2. What is that system cleared for? One FDA device category for PRP preparation systems (product code ORG) is defined around mixing PRP with bone graft material; hair loss is not the purpose written into that classification, so scalp use is a clinical decision rather than a labelled indication.
3. Who will inject me, and what is their qualification? The 2025 case report's authors call for administration by trained medical professionals.
4. What do you need to know about my medicines, and will you check with my prescriber rather than ask me to stop anything?
5. What should make me call you, and what number reaches a clinician out of hours?

If the cost side is the next question, the full-course arithmetic for PRP is set out on its own page, and what the trials measured as success is covered in the reading on PRP success rates. For anyone weighing a non-invasive route instead, the laser cap assessment reads each device against its FDA record; it involves no needles and has its own, different, list of limits.