Expand Your Diagnostic Potential with the Dermlite DL5

Expand Your Diagnostic Potential with the Dermlite DL5

Introduction

While dermoscopy and Wood’s lamps are both fundamental tools in the practice of dermatology, they have historically occupied separate spheres of utility. Thanks to the Dermlite DL5, these two modalities have now been merged into a single device.


If you're comfortable with traditional ("white light") dermoscopy and familiar with Wood’s lamp findings, then UV dermoscopy should feel intuitive.


Most importantly, the diagnostic value of UV-enhanced dermoscopy isn’t merely additive; the two modalities can work synergistically to uncover findings that would have remained hidden if either were used separately. Early evidence already shows value for scabies, fungal and bacterial infections, pigmented lesions, adnexal tumors, and more.

What Is UV Dermoscopy?

Simply put, UV dermoscopy uses UV light to illuminate the skin under dermoscopic magnification. The DermLite DL5 integrates true UV fluorescence at 10x magnification¹, bringing the utility of a Wood’s lamp directly into your hand.


Unlike many consumer ‘UV’ lights that operate at 395–405 nm (violet light that produces minimal fluorescence), the DermLite DL5 uses a true 365 nm UVA LED. This wavelength is optimal for inducing fluorescence in porphyrins, keratin, collagen, and microbial metabolites. In practice, this means clearer, brighter, and diagnostically meaningful fluorescence signals compared to higher-wavelength devices.


Under UV:

  • Endogenous or microbial molecules absorb UV and emit visible fluorescent light (green, blue, red, orange).
  • Many structures become visible that do not show under polarized or non-polarized dermoscopy.
  • Because the device is in contact with the skin, the findings are far more localized and precise than Wood’s lamp.

Scabies: The “Bright-Green Mite” (The Ball Sign)

Scabies under dermoscopy traditionally relies on the delta-wing jet sign. UV dermoscopy makes this dramatically more obvious.

Under UV:

  • The burrow fluoresces bright blue².
  • The female mite fluoresces bright green—a newly described phenomenon²˒³.
  • This green fluorescent dot at the end of the burrow has been termed the Ball Sign³.

Video 1. Bright-green fluorescence (“Ball Sign”) of a scabies mite under UV dermoscopy.

This finding is so visually striking that it helps:

  • Novices, who often confuse mites with debris².
  • Clinically ambiguous cases.
  • Test-of-cure, because the glow disappears when mites are no longer present².

Pediculosis (Lice)

Video 2. Demonstration of nit fluorescence under Wood's light to aid in the detection of pediculosis capitis.

Nits (lice eggs) and live lice exhibit a distinct bluish-white or pearly fluorescence. UV magnification aids with rapid screening to help differentiate viable nits from non-fluorescent pseudo-nits (hair casts or debris).

Erythrasma & Corynebacterial Infections

Video 3. Erythrasma Fluorescence under UV Light (365nm) Demonstrates the characteristic "coral-red" fluorescence of Corynebacterium minutissimum. 

  • Coral-red fluorescence from porphyrins appears far more localized under UV dermoscopy than under Wood’s lamp⁴.

Pitted Keratolysis

  • Pits become bright red-orange fluorescent clods under UV⁴.

Tinea Versicolor

  • Blue-green or yellow-green fluorescence from Malassezia metabolites⁴.

Pityrosporum Folliculitis

  • Follicular bright bluish-white fluorescence, making it easy to distinguish from acne⁵.

Pseudomonas

  • Characteristic green fluorescence from pyoverdine pigment⁴.

With the added benefit of magnification, you can distinguish:

  • folliculitis vs acne,
  • erythrasma vs candidiasis,
  • pseudomonas vs simple nail staining,
    within seconds.

Basal Cell Carcinoma (BCC)

Recently described UV signs include:

  • Multiple Aggregated Yellow-White (MAY) Globules, representing tumor-related fluorescence⁶.
    • Early studies suggest that MAY globules correspond to UV-fluorescent aggregates within basaloid tumor nests. Although this finding appears to be UV-specific and helpful for distinguishing BCC from other translucent papules, larger validation studies are still pending.
  • More conspicuous fluorescent rims or clusters than seen under white light.

Seborrheic Keratoses

  • UV “blink” sign: When examining SKs using standard “white light,” toggling into the UV mode will cause keratin-containing structures (esp. milia-like cysts) to suddenly “blink” into visibility.

Porokeratosis

  • The cornoid lamella shows a ring-like blue-green fluorescence, making borders unmistakable⁴.

Video 4. Double-edged peripheral scale (cornoid lamella) typical of porokeratosis.

Lentigo Maligna

  • UV reflectance often reveals sharper lesion borders, aiding margin assessment⁷.
    • Although UV reflectance can make LM borders appear sharper—particularly in chronically sun-damaged skin—it should be viewed as supportive rather than definitive. Border enhancement under UV does not replace clinical judgment, dermoscopic criteria, or, when appropriate, biopsy or reflectance confocal microscopy.

Hair & Scalp Disorders (Trichoscopy)

UV dermoscopy also aids in differentiating:

Scarring Alopecia

  • Absent fluorescent follicular dots yields a “follicular blackout”⁸.
    • “Follicular blackout” refers to the absence of the normally-present orange-red follicular fluorescence under UV (indicating destruction of follicular units in scarring alopecia).

Non-Scarring Alopecia

  • Retained orange-red fluorescence of follicular units remains visible.

Tinea Capitis

  • Bright green or yellow-green fluorescence localized to the hair shafts confirms infection by specific ectothrix species (e.g., Microsporum canis).
  • Magnification helps distinguish true hair shaft infection from fluorescent scalp debris and aids in targeted sampling for culture/KOH. However, absence of fluorescence does not exclude tinea capitis, as common endothrix agents (e.g., T. tonsurans) do not fluoresce.

Biopsy-Site Detection

UV dermoscopy makes prior biopsy sites appear as:

  • Dark, non-fluorescent areas with sharply defined borders⁷.

This is particularly useful in:

  • Actinically damaged skin
  • Scalp
  • Face (where scars blend in)

Surgeons report improved accuracy when locating prior biopsy sites before excision⁷.

Tips for Implementing UV into Your Dermoscopy Routine

Like any imaging modality, UV dermoscopy has boundaries. Highly keratinized, scarred, crusted, or densely pigmented surfaces may fluoresce poorly. Ambient light also reduces UV contrast, and fluorescence intensity can vary based on camera settings and distance from the skin.

  1. Use it selectively
    Start with scabies, erythrasma, tinea versicolor, BCC, and biopsy-site localization.
  2. Darken the room slightly
    Full darkness isn’t needed; just reduce ambient glare.
  3. Compare modes intentionally
    Toggle between polarized → non-polarized → UV.
  4. Document cases
    UV photos are valuable for patient education and for building your own image bank.
  5. Expect more evidence soon
    UV dermoscopy literature is growing quickly.

Clinically, UV dermoscopy is most powerful when interpreted in context rather than in isolation. Fluorescence highlights underlying chemistry, but diagnosis still hinges on correlating clinical morphology, standard dermoscopy, and patient history.

Conclusion

UV dermoscopy has proven itself to be a meaningful extension of our clinical examination, adding diagnostic contrast that white light cannot replicate.


If you already own a DL5, this capability is already at your fingertips, ready to be utilized. And if you don't? It’s certainly a feature worth prioritizing when you are ready for your next dermatoscope.


References

¹ Overview of UV dermoscopy and DL5 capabilities; near-UV fluorescence principles.
² Pietkiewicz P, Navarrete-Dechent C. Scabies Mite Is Bright Green Under UV Dermatoscopy. Dermatol Pract Concept. 2023.
³ Yürekli A. A new sign with UV dermoscope in the diagnosis of scabies: Ball sign. Skin Res Technol. 2023.
⁴ Sivakumar A, et al. Ultraviolet fluorescence dermoscopy in dermatology. CosmoDerma. 2025.
⁵ Silva AMG, et al. UV dermoscopy for Pityrosporum folliculitis. Dermatol Pract Concept. 2024.
⁶ Navarrete-Dechent C, et al. UV fluorescence in basal cell carcinoma (MAY globules). J Am Acad Dermatol. 2024.
⁷ Nazir HI, Daly KE, Seiverling EV. Ultraviolet-induced fluorescence dermoscopy: case series. J Clin Aesthet Dermatol. 2025.
⁸ Li X, Zhou C. UV-induced fluorescence dermoscopy in alopecia. J Am Acad Dermatol. 2024.


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