Fitzpatrick skin typing for laser hair removal

What the Fitzpatrick scale actually measures

Dermatologist Thomas Fitzpatrick published the scale in 1975 to dose ultraviolet phototherapy without burning patients. The original scale had four types; types V and VI were added later to cover darker skin.

The scale answers one question: how does this skin behave in light? Does it burn, does it tan, and in what order? It measures behaviour, not shade. That's why the questions you ask matter more than how the skin looks.

Two kinds of skin colour

Constitutive colour is the skin's genetic baseline, how it would look with no sun exposure. It doesn't change, and it's what the Fitzpatrick type describes.

Facultative colour is the skin today, after holidays, sunbeds or fake tan. It changes constantly, and it's what you see when the client sits down.

So type the skin underneath, and treat the skin in front of you. A type II client just back from holiday is still a type II, but may not be safe to treat at type II settings today, because the extra melanin in the epidermis competes with the hair for the laser's energy.

Four common typing mistakes

• Typing by ethnicity. Ethnicity isn't a skin type, and two clients from the same background can be two types apart.
• Typing by today's tan. This records facultative colour as the type, so the client is typed too high.
• Letting the client self-type. Clients often guess wrong, most often too low.
• Typing once and never again. Skin, medication and lifestyle change, so re-check every session.

The four consultation questions

• What happens after an hour in strong sun with no protection: a burn, pink then brown, or straight to brown?
• Do you tan, and how quickly?
• What colour is your skin where the sun never reaches, such as the inner upper arm?
• Any sun, sunbeds or fake tan in the last four weeks? This doesn't change the type. It decides whether you treat today.

Ask about pigment history and medication separately. A history of dark marks after spots or bites, melasma, keloid scarring or photosensitising medication won't change the type, but it should change the treatment.

What the skin type changes

Skin type guides your choice of wavelength. 755 nm (alexandrite) has the highest melanin absorption and suits lighter skin. 810 nm (diode) is a middle ground for most types. 1064 nm (Nd:YAG) is the least absorbed by surface melanin and is the usual choice for darker skin.

Higher types generally need lower fluence, longer pulse durations, good cooling and a gradual build-up. Exact settings depend on your machine, so always start from the manufacturer's protocol. The type is your starting point, and a patch test at your intended settings, on the area you'll treat, confirms it.

Learn it properly: Fitzpatrick in Practice

Fitzpatrick in Practice is a short online masterclass for laser technicians and for clinics training their teams. It covers the scale, consultation questions, tanning, pigment history, medication, wavelength, settings, patch testing and record keeping, with real-world cases.

• Video masterclass you can watch at your own pace
• Short quiz at the end
• Certificate of completion for every learner who passes
• £25