Clinical guide

IPL Complications and How to Avoid Them

Most IPL complications trace back to six things: fluence set too high for the phototype, a cut-off filter that's too short, cooling that failed or lost contact with the skin, recently tanned skin, pulses stacked on the same spot, and a photosensitising medication nobody asked about. This guide takes each one through what your client sees, the first hour done properly, and the weeks after, plus a red-flag list for when a burn stops being your problem and becomes a doctor's. It's educational material for people buying and running equipment, not medical advice.

Normal reaction, or a complication?

Half the alarming calls a clinic takes next morning aren't complications. Our device manuals describe a scalding sensation for half an hour to two hours after a pass, then flushing for four to twelve hours, and our archive's guide puts the spotty follicular reaction after hair removal at two to twenty-four hours. Normal shows within hours, not on day three, and settles inside 24 to 48 hours. No pus. No fever.

Four findings break that pattern, and none are yours to manage: pustules in crops around the follicles, anything fresh or worsening after 48 hours, clustered small blisters with burning or tingling that started before the rash, and weeping with honey-coloured crust or a temperature. Treat those as infection, not irritation: stop the course, refer. Our skin disease atlas manages concurrent infection with antibiotics or antivirals and folliculitis with deep cleansing plus a topical antibiotic ointment twice daily, all on a clinician's say-so. Herpes 1 or 2 in the treatment field is a flat contraindication in our archive guide, and cold sores nearby mean antiviral cover first, which StatPearls also advises.

Six causes behind most of it

Thaysen-Petersen and colleagues, in a randomised controlled trial in Lasers in Surgery and Medicine, reported that skin pigmentation, fluence level and ultraviolet exposure all bear on side effects. StatPearls is blunter: untrained operators using excess energy cause thermal damage.

Cause	Client sees	First hour	Following weeks
Fluence too high for the phototype	Pain past the usual snap, blanching, deepening red	Stop, then the four steps below	Photoprotection, no exfoliation for a week, restart lower
Cut-off filter too short	Darkening across the whole field, not just the lesions	Stop, check the filter fitted, write it down	Manage as pigment injury, re-plan on a longer cut-off
Cooling failure or poor contact	A burn with edges, tracking the crystal rim or a dry patch	Stop. Cool running water, at least 20 minutes, no ice. Cover loosely, log, photograph	Burn aftercare and a booked review
Recently tanned skin	A burn at settings fine six weeks ago	Catch it at consultation, or stop mid-pass and cool as above	Our archive guide bars sun or solarium exposure in the four weeks before treatment. Wait it out, re-test
Pulses stacked on one spot	A blister, or a bright band where footprints overlapped	Stop. Cool water, at least 20 minutes, no ice. Don't burst it. Non-stick cover, parameters and photos on file	A partial-thickness burn healing over days to weeks. StatPearls ties reheating to scarring and pigment loss
Photosensitising drug missed at screening	Swelling out of proportion to the energy used	Stop, cool, arrange same-day medical review	Our manuals flag corticosteroids for marked oedema. Drug question back on intake

Whatever the cause, the first hour runs in one order. The first move is not ice, and the handpiece stays out of use until chiller, window and gel are checked.

Stop. No finishing the other cheek.
Cool under cool running water for at least 20 minutes. That's ANZCOR's figure, and it rates cooling as worth starting up to three hours after the burn, sooner being better. Never ice, never an ice pack on burnt skin. ANZCOR is explicit that ice or iced water may cause further tissue damage.
Cover, don't burst. A loose non-stick dressing, or cling film laid over the cooled burn rather than wrapped round it, which is how the NHS puts it.
Record it while it's fresh. Filter, fluence, pulse width, gap, pulse count, handpiece, region, operator, time. Photograph it, give written aftercare and a review date.

Some of it needs a doctor today:

Burning or blistering on the face, around the eyes, or on hands, feet, genitals or a joint. ANZCOR counts those sites significant whatever the size.
Blistering across a broad area, or skin that looks white, waxy or leathery.
Spreading redness, pus, fever.
Pain still climbing after proper cooling, or a wound that stalls.
Any real doubt about depth. Guess late, and you're guessing about a scar.

DermNet's roll-call of photosensitisers runs longer than most consent forms assume: tetracyclines, fluoroquinolones, amiodarone, NSAIDs, oral retinoids, even St John's wort. Our device manuals head their contraindications with that risk, naming tetracycline. So "any medications?" is the wrong question. "Anything new this month?" is the right one.

Why fluence and phototype sit at the top

Our engineering archive works one example that belongs laminated to the console. Hold energy density constant. A melanin-rich follicle coagulates progressively at a 100 ms pulse, while the epidermis under that same energy density hits its damage threshold at 99 ms. The epidermis goes first. That millisecond is a deficit, not a margin. Cooling buys it back, and cold gel carries the cold in from the sapphire window, so gel applied afterwards does nothing.

Glass is your other control, an idea traced to Anderson and Parrish's 1983 selective photothermolysis paper. Our device manuals list cut-offs of 530-1200 nm for rejuvenation, 585-1200 nm for vascular lesions and 610-1200 nm for hair removal, and the longer cut-off goes on darker skin because melanin absorbs hardest at the short end. Timing carries the rest. Darker skin wants a longer gap between pulses so the epidermis sheds heat before the next one lands, and epidermal temperature must stay below the point where protein coagulates, a threshold that shifts with pulse width and cooling rather than sitting at one safe number. Working figures come from the Fitzpatrick parameter tables shipped with your unit and from that client's test spot, not off a web page.

Post-inflammatory hyperpigmentation, the one you'll meet

PIH turns up late, so clients never connect it to the session. Our archive's clinical guide describes darker patches appearing a couple of weeks after treatment and lasting from two weeks up to a year, higher risk in darker skin, and separates it from the darkening you want when treating a lentigo. Davis and Callender, whose review of PIH in skin of colour ran in the Journal of Clinical and Aesthetic Dermatology, put inflammation control ahead of topical depigmenting agents and photoprotection. Our skin disease atlas agrees: calm it, keep it out of the sun, hydroquinone at 1 to 4 per cent twice daily under a clinician's direction.

Don't fire into PIH to even it out. That's adding inflammation to an inflammatory pigment response, and charging for it. Park the course, refer, photograph monthly, and when tone returns restart lower on a longer cut-off, as our pigment and lentigo treatment guidance sets out. Any new, changing or atypical lesion goes to a clinician first, with dermoscopy or biopsy where indicated.

Hypopigmentation, and the honest version

Rarer. Considerably worse, because there's no reliable rescue. Our archive's clinical guide says white patches can last from two weeks up to a year and carry the potential to be permanent, darker skin more at risk. Our skin disease atlas adds that most clients who lose pigment had prior sun exposure, and that no treatment is generally offered. That's a prognosis, not reassurance.

So the plan is prevention. Our device manuals give three moves for at-risk skin: widen the pulse width, widen the pulse gap, drop the energy density. Jayanata, Ibrahim and Rodrigues, writing in the Australasian Journal of Dermatology on the risks of IPL in skin of colour and on optimising safety in Australia, make the same case. If a phototype makes a broadband lamp uncomfortable, the honest answer is a longer wavelength: an 808 nm diode such as the DL-07, banded in our hair removal guidance.

Consent, records and the insurance call

Frame this as prevention, not fear. Clinics that document well make fewer mistakes, because writing a number down forces you to look at it. Lin and colleagues, revisiting IPL safety in Photodermatology, Photoimmunology and Photomedicine, conclude that candidate selection, optimal parameters and standardised protocols are all necessary.

Consent that names the injuries: temporary or permanent hyper- or hypopigmentation, erythema, crusting, blistering and scarring, per StatPearls. Say permanent out loud.
A written burn protocol on the wall: cooling, covering, recording, referral thresholds. Nobody improvises well with a crying client in the chair.
Test spots within three days of treatment, as our archive guide specifies, plus a settings log for every pass. Can't reconstruct a session, can't defend it.
Dated medication and tan history every visit, since prescriptions change between sessions and so do holidays. Goggles and eye patches ride the same habit.
Training records, then the insurance conversation before you buy. Our device manuals require operators to qualify through training and ship parameter tables by Fitzpatrick type. Is IPL named on the policy? Who may operate it? Does cover hang on documented training?

Commissioning and operator training run through our installation and after-sales service.

FAQ

Her pigmentation looks worse two weeks on. PIH, or failure?

Look at the pattern, not the shade. Treating a lentigo on purpose darkens the lesion itself, which scabs and sheds in roughly three to ten days per our device manuals. PIH is broader, later, and follows the treated field or handpiece footprint. Stop, photograph, refer.

How long before we re-treat an area that blistered?

Weeks, not days, and not until the colour settles. A caution on our own paperwork: the archive guide's line about blistering settling in about two hours with ice fits the immediate scalding flush, not a formed blister, so we don't follow it. An IPL blister is a partial-thickness burn. Cool, cover, document, refer against the red flags above, then go back lower.

Does better hardware genuinely reduce complications?

Partly. Stable output stops peak energy sagging across the pulse train, which is what tempts operators into double-firing, and contact cooling protects continuously rather than in bursts. Fine energy steps let you drop a notch for a type IV instead of jumping a band. No machine fixes a missed medication.

Evidence & further reading

Educational material for equipment selection and operator training. It is not medical advice, a treatment protocol or a promise of clinical outcome.

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