The Wood lamp is mainly used to diagnose pigmentary abnormalities, skin infections and porphyrias. Pigment Alteration Diseases
(i) Hypopigmentation and depigmentation.
1, vitiligo: bright white fluorescence with increased contrast is obvious.
2, pityriasis simplex: post-inflammatory depigmentation, contrast increased inconspicuous.
3, tuberous sclerosis, anaplastic nevus: contrast increased inconspicuously.
4.Itochromatosis: the contrast increases inconspicuously.
(II) Pigmentation.
1.Chloasma: epidermal type, contrast increase is obvious. Dermal type, showing light blue under natural light, and the color does not deepen when examined under Wood lamp.
2.Nevus of Ota: contrast increase is not obvious.
3. Freckles: contrast increases obviously.
4.Pigmented dry skin disease: contrast increase is not obvious.
5.Caffeinated spots: the contrast increases inconspicuously.
Infectious diseases
(i) Bacteria
1.Erysipelas: showing coral red fluorescence.
2.Acne: showing orange-red fluorescence. The intensity of fluorescence in facial follicles is significantly related to the number of Propionibacterium acnes. Acne vulgaris: showing yellow-white fluorescence.
3. Pseudomonas aeruginosa infection: showing yellow-green fluorescence.
4. Axillary tinea: showing dark green fluorescence.
5. Pseudomonas spp.: showing green fluorescence.
(ii) Fungi.
1. Dermatophytes: Tinea capitis: specific fluorescence is seen in hair follicles of broken hair or plucked hair. Bright green fluorescence is seen in Audu Ang, canis minor, skew, rust and plaster-like microsporidia infected individuals. Trichophyton hirsutum can show a faint blue fluorescence or a dark green fluorescence. In contrast, Trichophyton rubrum and Trichophyton verrucosum do not fluoresce under Wood’s lamp.
2. Ringworm: shows yellow-white fluorescence or copper-orange fluorescence.
3, Tinea albicans: show bright green fluorescence.
(iii) Other.
1. pubic lice: the pubic hair stem is covered with pinhead-sized white fluorescence.
2. scabies: grayish-white tunnels are easily detected in the finger crevices, wrist side and male glans.
Abnormal porphyrin metabolism diseases
In patients with late-onset cutaneous porphyrias, their urine specimens show bright pink and orange fluorescence under Wood’s lamp. In congenital porphyria teeth, urine, and bone marrow may show red fluorescence. In erythropoietic protoporphyria, blood red blood cells fluoresce transiently under a fluorescence microscope. In contrast, urine is nonfluorescent.
Other
1, squamous cell carcinoma: shows bright red fluorescence.
2, contact dermatitis: shows the distribution of certain allergens in the skin.