Wood’s Lamp Skin Examination in London

What is Wood’s Lamp Examination?

A Wood’s lamp is a handheld diagnostic device that emits long-wave ultraviolet light (UV-A). When directed at the skin in a darkened room, it causes certain substances to fluoresce, revealing hidden changes not visible to the naked eye. This includes pigmentary disorders, vitiligo, bacterial and fungal infections, acne porphyrins, and subtle differences in skin texture.

At Skinhorizon Clinic, Wood’s lamp examination is performed by our consultant dermatologist as part of a targeted assessment. It is quick, painless, and provides immediate diagnostic clues that guide whether further tests — such as cultures, swabs, or biopsies — are necessary.

When is it recommended?

Wood’s lamp examination is recommended whenever skin changes are unclear under normal light or when subtle infections or pigmentary shifts are suspected. Common scenarios include:

• Pigmentary disorders: Melasma, Vitiligo, hypopigmentation, post-inflammatory pigmentation
• Infections: Tinea (fungal infections), erythrasma (bacterial), pityriasis versicolor
• Acne activity: Porphyrins produced by Cutibacterium acnes fluoresce orange-red
• Skin damage: Sun damage, thickened stratum corneum, or subtle barrier defects
• Hair and scalp assessment: Certain fungal infections of the scalp fluoresce under UV light

For many patients, the Wood’s lamp helps narrow down diagnosis instantly, guiding whether laboratory confirmation is necessary.

How it works

1. Preparation: Performed in a darkened room; the area of concern is cleaned and dried if needed.
2. Illumination: The Wood’s lamp is held close to the skin, emitting long-wave UV light.
3. Observation: Consultant examines changes in colour and fluorescence — e.g., bright white, yellow-green, coral-red, or blue hues.
4. Interpretation: Findings are linked with clinical examination and history to reach a diagnosis.
5. Next steps: If required, confirmatory swabs, cultures, or biopsies may be arranged.

What can it help assess?

• Vitiligo: Bright white or chalky fluorescence distinguishes depigmentation
• Melasma: Epidermal pigment fluoresces clearly, helping define treatment
• Fungal infections: Some dermatophytes show green or blue-green fluorescence
• Erythrasma: Coral-red fluorescence due to porphyrins of Corynebacterium
• Acne: Orange-red fluorescence from porphyrins helps assess activity
• Sun damage: Subtle areas of photodamage highlighted by uneven fluorescence

Wood’s lamp can be used alongside digital skin analysis or dermatoscopy to improve diagnostic precision and track progress in chronic conditions.

Preparation

• Avoid applying creams, make-up, or deodorants on the area before the test — they may fluoresce and alter interpretation.
• Ensure skin is clean and dry.
• Remove nail varnish if nail assessment is required.

Safety & limitations

Wood’s lamp examination is safe and painless. The UV light used is low-intensity and does not cause skin damage. Limitations include: not all fungi fluoresce, some pigmented lesions may require dermatoscopy or biopsy for confirmation, and external products can interfere if not removed.

Results & follow-up

Results are immediate. Your consultant explains the findings during the appointment and outlines next steps, whether reassurance, treatment, or further diagnostic tests. In chronic conditions such as vitiligo or melasma, repeat Wood’s lamp exams can be used to monitor progress objectively.

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Disclaimer: Diagnostic tests at Skinhorizon are provided only where clinically appropriate and must be interpreted by a qualified healthcare professional. Results alone do not replace a medical diagnosis, and further consultation may be required.