Point a standard dermatoscope at a lesion and you get one story: what the surface and near-subsurface look like under white light. Switch to ultraviolet, and the same patch of skin can tell a completely different story, written in fluorescence rather than color. This is the basis of Wood's lamp examination, a technique with a surprisingly long clinical history and a growing body of modern research behind it.

A 100-Year-Old Technique That's Still Evolving

The Wood's lamp was invented in 1903 and put to clinical use in dermatology by 1925, originally to spot fungal infections of the hair and scalp. That makes it one of the oldest diagnostic light sources still in routine use, a milestone that a recent review in PMC marks as its 100th anniversary in medicine. What's changed isn't the underlying principle, but the hardware. Classic Wood's lamps used mercury vapor bulbs behind a filter; modern versions use LED arrays that hit a similar 365 nm peak with far more consistent output and none of the warm-up time.

Why UV Light Reveals Things White Light Can't

Skin isn't uniformly reactive to ultraviolet light. Collagen, certain bacterial byproducts, fungal metabolites, and porphyrins all fluoresce differently under UV, while melanin absorbs it  -  making contrast possible. As a dermatology imaging review published in Clinics in Dermatology explains, this variability in how skin structures fluoresce is what allows UV examination to surface disease patterns that are effectively invisible under conventional lighting.

In practice, that means UV illumination is commonly used to help evaluate:

• Fungal and bacterial infections: species like Microsporum and Malassezia can fluoresce green or gold, and Pseudomonas-related nail and wound infections can show a distinct green glow, per a 2025 clinical review of Wood's lamp applications.
  
  
• Pigmentary disorders: vitiligo tends to produce a sharply defined blue-white glow because there's no melanin left to absorb the UV, which is why Cleveland Clinic lists pigment-loss conditions among the most common reasons for a Wood's lamp exam.
  
  
• Subclinical findings not yet visible to the eye: a 2025 case series in the Journal of Clinical and Aesthetic Dermatology documented conditions including porokeratosis and early lentigo maligna where UV-induced fluorescence dermoscopy changed the diagnostic picture compared to standard polarized dermoscopy alone.

It's Not a Magic Wand, and the Research Says So

Good clinical content doesn't oversell a tool. A preliminary study of 23 patients with suspected fungal infections in the Dominican Republic found that while several lesions fluoresced under UV, not all of them corresponded to a positive microscopy result, and several confirmed infections didn't fluoresce at all. The authors concluded that Wood's lamp alone isn't a reliable stand-in for lab confirmation in every case; it's a screening aid, not a replacement for it. That nuance matters, and it's part of why UV illumination is best used alongside standard clinical judgment and lab testing.

Why "Variable" UV Settings Specifically Matter

Not every fluorophore lights up at the same wavelength. A single fixed UV setting will surface some findings clearly and miss others. This is the reasoning behind building dermatoscopes with more than one UV wavelength rather than a single fixed setting. Different wavelengths excite different compounds in skin, so being able to switch between them in the same exam, without swapping devices, gives a clinician more of the diagnostic picture in less time.

Two Ways ILLUCO Puts This Into Practice

ILLUCO's dermatoscope lineup takes two different approaches to UV, depending on what a practice needs most:

IDS-3100 Wood's Lamp - True Variable UV

The IDS-3100 is built specifically around wavelength flexibility. Its 70-LED array (64 white + 6 UV) cycles through cross-polarized, parallel-polarized, UV 365 nm, UV 405 nm, and a combined 395+405 nm mode - four distinct configurations in one handheld device. That range is what makes it useful across a wider set of findings: pigment disorders like vitiligo and melasma, cutaneous fungal and bacterial infections, and subsurface melanin mapping, without reaching for a second instrument. We've gone deeper on this device in an earlier post, The Modern Wood's Lamp: The ILLUCO IDS-3100.

IDS-9100 - 12x Magnification With Built-In UV

ILLUCO IDS-9100 dermatoscope with 12x optical magnification and smartphone attachment

The IDS-9100 takes a different approach. It's the first dermatoscope to reach 12x optical magnification, paired with 0.006 mm resolution and 40% less optical distortion than leading competitors. Its UV illumination is fixed at 365 nm (18 mW) rather than switchable across wavelengths, but it's built into an instrument for high-resolution lesion mapping and cross/parallel polarization, with UV available as an added layer rather than the primary feature. For clinicians whose main need is maximum magnification and image clarity with a single UV reference point, that trade-off makes sense.

Choosing Between Dermoscopy Devices

Full specs for the whole lineup, including the IDS-1100 and IDS-1000 Plus, are on the ILLUCO dermatoscopes collection page, and general questions on polarization modes are answered on our dermatology resource page.

Frequently Asked Questions

Does UV light on a dermatoscope replace a biopsy or lab test?
No. UV/Wood's lamp findings are a screening aid that can support a clinical decision, not a substitute for histopathology or culture when those are indicated.

Is UV light from a dermatoscope safe for patients?
Wood's lamp examinations are widely described as painless and low-risk, with the main precaution being to avoid prolonged direct eye exposure to the UV source, per NCBI's clinical overview of Wood's light.

Why would I need more than one UV wavelength?
Different skin fluorophores respond to different wavelengths, so a device that can switch between 365 nm, 405 nm, and a combined mode surfaces a wider range of findings than a single fixed wavelength.

Explore ILLUCO's Dermatoscope Lineup

Whether the priority is comprehensive UV-assisted screening or maximum-resolution lesion mapping, ILLUCO's dermatoscopes are built for clinical use every day. Browse the full collection, or reach out and contact us for guidance on which model fits your practice.