Wood Lamp Skin/ Hair Screening

Wood Lamp Skin/ Hair Screening

How does a wood lamp check work?

Checking the skin or nail lesion with wood lamp involves shining a hand-held wood lamp device on the area of concern by your physician. Ideally the procedure is done in a dark room. Upon shining, certain skin and nail conditions may glow, hence aiding the diagnosis of skin condition.


  • Quick
  • Painless
  • Safe
  • Useful in aiding diagnosis

What is a wood lamp screening used for?

  • It is suitable to rule in and out differentials including:
  • Fungal infections (tinea infection)
  • Pityriasis versicolor
  • Erythrashma
  • Pigmentation disorders such as vitiligo, melasma
  • Bacterial infections
  • Head lice/nits
  • Porphyria cutanea tarda

What results can I expect?

With the wood lamp examination, different skin condition may glow and emit out different color, this will help the physician to nail down an accurate diagnosis allowing effective treatment to be delivered to patient.

How many sessions do I need?

One session is usually sufficient for doctor to physically examine the skin area with wood lamp.

Wood Lamp Skin/ Hair Screening


You are advised to avoid make up, deodorant, body spray, perfume, moisturizer or sunblock as the chemicals in the product may affect the results of wood lamp examination.

Wood lamp is a light emitting lamp, shining black light with wavelength 320-450 nm. Our human naked eyes are not able to discern black light as its wavelength is shorter than the wavelength of ultraviolet. The black light can be absorbed by our body tissues such as melanin, collagen and the tissues will then emit out a longer wavelength that is within visible spectrum, hence allowing a ‘glow/ fluorescent’ to be seen by our naked eyes.

Wood lamp black light does not cause cancer or harm the skin/ body. As the wood lamp does not shine out UVB wave lengths, no skin damage will occur. Wood lamp generally does not cause sun burn or sun damage, though it can cause rash in patients who are photosensitive. Nonetheless, as the duration of skin examination with a wood lamp is not too long, there is usually no downtime or side effect from wood lamp test.

Although the black light from wood lamp does not cause blindness, it may cause some eye discomfort. Your doctor will advise you to close your eyes if the wood lamp is being shone onto your face/eye region.

General healthy skin appears blue in color under the black light from wood lamp. The skin areas that are dryer may appear purplish in color. Sometimes in thicker part of our skin, we may notice white spots under the wood lamp.

This is because our teeth and nails have high concentration of a mineral known as phosphors. Under black light, our body parts with phoshors will fluoresce and glow.

Fungal infections such as ring worm or tinea infection (over the scalp, body) can fluoresce blue green under black light. However, sometimes, the lesions may also appear dull blue.

Bacterial infection secondary to pseudomonas bacteria can fluoresce as a bright green glow under the black light. This can sometimes be seen at sloughy wound or ulcers that takes prolonged time for healing.

Bacterial infection such as Corynebacterium infection leading to erythrasma patches over the groin, armpit can fluoresce as coral-red under the emission of black light from a wood lamp. It is important to different this findings from fungal infection as the treatment differs in both conditions.

Lice/ nits can appear white under the black light from wood lamp. The nits that are empty may appear grey in color. This is useful to detect head lice, pubic lice among the hair follicles.

Yes. The use of black light from a wood lamp allows the accentuation of the borders of the pigmentary skin condition. Black light also highlights the differences in pigmentation in dermis/epidermis. This will help the physician in the diagnosis of pigmentary disorders such as vitiligo, post inflammatory hypopigmentation, melasma and etc.

In certain type of inflammatory acne secondary to bacteria (cutibacteria), acne lesions can glow orange-red under black light. This allows physician to target their treatment regimen against the bacterial infection.

Although wood lamp are not used to diagnosed skin cancer, it can be used as an adjunct to facilitating a physician in detecting a regressed melanoma, the borders of pigmented skin cancers and pigmented moles. Depending on your skin condition, your doctor will guide you further during physical examination on the suitability of using a wood lamp.

Contact Us