A localised bald patch after surgery or prolonged immobility can be pressure alopecia, caused by sustained pressure on part of the scalp. Some cases regrow over the following months, while severe injury can scar. The diagnosis and condition of the skin need checking before a treatment such as PRP is considered.
Hair loss after an operation is distressing, particularly when it appears after the immediate recovery has passed. The useful first step is to distinguish a focal pressure-related patch from general shedding or another scalp disorder, rather than assume all postoperative loss follows the same pattern.
What is pressure alopecia after surgery?
Pressure alopecia has been described after operations under general anaesthesia and after prolonged immobilising illness. Published reports link it to reduced blood flow in scalp tissue exposed to sustained pressure. The back of the head is a common location because it may have rested against a support.
A patch may become apparent after a delay. A 2015 clinical series described onset several weeks after the pressure exposure. A 2026 case series after robotic gynaecological surgery also reported delayed focal loss, sometimes preceded by soreness or swelling. Neither establishes an exact timetable for everyone.
Do not assume the anaesthetic medicine itself has damaged every follicle. The position and pressure history are important parts of this particular diagnosis. A clinician needs to consider other explanations too, especially if the pattern, timing or examination does not fit.
Arrange an assessment of a new patch after surgery.
How is a patch different from general postoperative shedding?
Widespread shedding and a clearly localised bald area are not the same presentation. Our guide to hair loss after illness or surgery covers the broader issue. This article addresses a focal patch over a possible pressure-bearing area.
The clinician will want to know when the operation or illness occurred, how long you were immobile and where the scalp was supported. Note whether there was pain, swelling, a sore, crusting or skin breakdown before the hair loss. Bring any discharge information and photographs, while recognising that surgical teams may hold details you do not know.
Other conditions, including patchy autoimmune loss and inflammatory scalp disease, may need consideration. A patch that resembles an online example still needs assessment. An examination can help determine whether follicle openings remain visible and whether there are signs of scarring or ongoing inflammation.
Will the hair grow back?
It may, but a personal guarantee would be misleading. The 2015 report described both complete recovery and permanent scarring among referred patients. That was a small clinical series, not a population prediction or a PRP trial.
The 2026 report described six patients with pressure-related scalp findings after robotic surgery; two developed localised alopecia and later regrew hair. It adds a recent description of the problem, but it cannot prove that all postoperative patches recover or that a particular treatment caused recovery.
The outlook depends on the nature and severity of the tissue injury. A clinician may recommend observation with documented follow-up when findings are reassuring, or specialist assessment if there is uncertainty or evidence of damage. Ask what changes would be expected, when to review and what would trigger further investigation.
Should I have PRP to speed recovery?
The reports used for this guide do not establish PRP as a proven treatment for pressure alopecia. Spontaneous regrowth in a condition that can recover makes before-and-after photographs especially difficult to interpret as evidence of a procedure's effect.
PRP evidence from pattern hair loss cannot simply be transferred to a patch caused by pressure injury. If the follicles have been replaced by scar, promising that growth factors will recreate them is not justified. If the skin is still sore, broken or inflamed, the clinical priority is assessment and appropriate care, not a cosmetic injection timetable.
The London PRP Clinic's services page describes its doctor-led hair treatments. Suitability is a separate decision. An assessment can help clarify the diagnosis and referral need without committing you to a PRP course.
Discuss whether a hair procedure belongs in your plan.
What information makes the consultation more useful?
Bring the date and type of operation, the sequence of scalp symptoms and images showing how the area has changed. Include your medicines and any other recent illness. If the surgical team has already reviewed the patch, bring their advice and any dermatology report.
Ask whether the pattern is typical of pressure alopecia, whether scarring is suspected and whether a closer scalp examination or biopsy would help. Ask who will follow the patch and how to contact them if it changes.
It can be helpful to take photographs in similar lighting and from the same angle over time. Avoid judging progress from different hair lengths, wet versus dry hair or strongly changed lighting. Documentation supports review; it does not replace an examination or diagnose regrowth on its own.
When should I contact a clinician sooner?
A painful or open scalp lesion, increasing redness, discharge or worsening swelling needs advice, especially if you are unwell. Contact the treating team or an appropriate medical service rather than waiting for a routine hair appointment. Rapidly worsening symptoms should be assessed urgently.
For future surgery, tell the surgical and anaesthetic teams about any previous pressure-related scalp problem. The literature discusses padding and position checks where feasible, but those decisions belong to the operating team. Do not try to set your own intraoperative positioning plan from a hair article.
The aim is a clear explanation and an honest recovery plan. You should know what is being monitored, which treatment has evidence for your diagnosis and which promises would go further than the available research.
Evidence and sources
Pressure alopecia, clinical findings and prognosis, JAAD 2015 and the 2026 robotic surgery case series support the pressure-related mechanism, delayed presentation and variable prognosis. These are observational reports, not trials of PRP. Sources checked 4 November 2026. This is general information and does not diagnose a postoperative complication.