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Dermoscopy Basic Principles

Non-invasive in-vivo skin imaging technique using a handheld dermatoscope (10-20x magnification with cross-polarized or non-polarized illumination) revealing subsurface structures invisible to the naked eye; cornerstone of modern dermatology improving melanoma diagnostic accuracy by 30-50 percent.

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Dermatoloji department. Book Appointment →

What is Dermoscopy Basic Principles?

Dermoscopy (dermatoscopy, epiluminescence light microscopy ELM, incident light microscopy, surface microscopy, skin surface microscopy SSM) is a non-invasive in-vivo skin imaging technique using a handheld dermatoscope to visualize morphological features in the epidermis, dermo-epidermal junction, and superficial dermis. Originally developed in the 19th century by Pierre Saemisch (1879) using simple lenses, modernized by Pehamberger and Wolff in 1980s with handheld dermatoscope and codified diagnostic algorithms by Argenziano, Stolz, Menzies, and Soyer in 1990s-2000s.

Optical principles: 1) Skin surface naturally reflects most incident light, obscuring deeper structures; 2) Contact dermoscopy with immersion fluid (alcohol gel, mineral oil, ultrasound gel) eliminates surface reflection by matching skin refractive index, transmitting light into deeper layers; 3) Polarized dermoscopy (cross-polarized light) uses two perpendicularly oriented polarizing filters — eliminates surface reflection without contact, allows visualization of dermal structures and vascular patterns; 4) Hybrid dermatoscopes (DermLite DL4, Heine Delta 30, FotoFinder Hybrid) combine both contact and polarized modes for complementary information.

Equipment: 1) Handheld dermatoscope (10x magnification standard, 20-30x in advanced models, manual focus or LED illumination, polarized or contact mode, examples Heine Delta 20T/30, 3Gen DermLite DL3/DL4/DL5, FotoFinder Studio); 2) Smartphone adapter (Heine HSL 150, 3Gen DermLite Pro, MoleScope) — democratized dermoscopy via mobile devices; 3) Photographic dermatoscope (DSLR with mounted dermatoscope, 12-24 megapixel images for digital archiving); 4) Total body imaging systems (FotoFinder Bodystudio ATBM, Canfield Vectra WB360, MoleMax HD) — enable longitudinal monitoring.

Symptoms

Pigmented skin lesion requiring evaluation (any nevus, suspected melanoma)
Atypical mole syndrome (multiple dysplastic nevi)
Suspected basal cell carcinoma (pearly papule with telangiectasia)
Suspected squamous cell carcinoma (hyperkeratotic lesion, ulcer)
Actinic keratosis differentiation from squamous cell carcinoma
Seborrheic keratosis differentiation from melanoma
Inflammatory skin disease pattern recognition (psoriasis, lichen planus, scabies, alopecia)
Patient with personal or family melanoma history requiring surveillance

Risk Factors

Operator inexperience (steep learning curve, sensitivity 80-90 percent only with trained examiner)
Equipment limitations (low magnification limits some details)
Patient skin type (heavily pigmented skin difficult to interpret, more difficult diagnosis in Fitzpatrick types V-VI)
Anatomical site (acral lesions, facial lesions have unique patterns requiring specific algorithms)
Hair, scale, ulceration interfere with view (require shaving, removing crust, biopsy)
Time consumption (1-2 minutes per lesion adds to clinic visit)
False reassurance (negative dermoscopy does not exclude all melanomas, especially nodular and amelanotic)
Cost (basic dermatoscope $200-$400, advanced systems $1,000-$50,000)

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Any pigmented skin lesion requiring evaluation
  • Atypical mole or suspicious skin lesion concerning for melanoma
  • Personal or family history of melanoma (annual surveillance)
  • Multiple atypical nevi (5+ atypical lesions)
  • Photodamage with multiple actinic lesions (skin cancer screening)
  • Patient request for skin cancer screening
  • Pre-excision evaluation of suspected non-melanoma skin cancer
  • Hair loss evaluation (trichoscopy)
  • Inflammatory skin condition diagnosis aid

Treatment Methods

01
Two-step algorithm (Argenziano): Step 1 — distinguish melanocytic vs non-melanocytic lesions (melanocytic features include pigment network, aggregated globules, streaks, homogeneous pigmentation, parallel pattern on acral); non-melanocytic features include milia-like cysts, comedo-like openings (seborrheic keratosis), arborizing telangiectasia (basal cell carcinoma), ulceration with leaf-like areas (BCC), red-blue lacunes (hemangioma); Step 2 — for melanocytic lesions, distinguish benign vs malignant using pattern analysis, 7-point checklist, 3-point checklist, ABCD rule, or Menzies criteria
02
7-point checklist (Argenziano): Major criteria (2 points each) — atypical pigment network, blue-white veil, atypical vascular pattern; Minor criteria (1 point each) — irregular streaks, irregular dots/globules, irregular pigmentation, regression structures; Total >= 3 points = consider melanoma, biopsy recommended; sensitivity 95 percent for trained examiner, specificity 75 percent
03
ABCD rule (Stolz): Asymmetry (0-2 points), Border sharpness in 8 octants (0-8 points), Color (1 point per color: white, red, light brown, dark brown, blue-gray, black; max 6), Diversity of structures (network, structureless area, dots, globules, branched streaks; max 5); Total Dermoscopy Score (TDS) = 1.3A + 0.1B + 0.5C + 0.5D; TDS < 4.75 = benign, 4.75-5.45 = suspicious (consider follow-up), > 5.45 = melanoma (excise)
04
Pattern analysis (Pehamberger, Argenziano): identifies global pattern (reticular, globular, cobblestone, homogeneous, starburst, parallel, multicomponent, unspecific) and local features (pigment network, dots, globules, streaks, blue-white veil, regression structures, vascular structures, structureless areas); pattern recognition with experience yields highest accuracy (sensitivity 90-95 percent, specificity 90 percent in expert hands)
05
Vascular pattern recognition: comma vessels (intradermal nevus), dotted vessels (Spitz nevus, melanoma in situ), hairpin vessels (seborrheic keratosis, keratoacanthoma), glomerular vessels (Bowen disease, squamous cell carcinoma in situ), arborizing telangiectasia (basal cell carcinoma), polymorphous vessels (melanoma), strawberry pattern (actinic keratosis on face), milky-red areas (melanoma)
06
Special anatomical sites: face (pseudonetwork from hair follicles, gray dots and globules in lentigo maligna, asymmetric follicular openings in lentigo maligna, polygonal lines in lentigo maligna melanoma), acral skin (parallel furrow pattern benign in 80 percent, parallel ridge pattern suspicious for acral melanoma in 90 percent, lattice pattern, fibrillar pattern, peas in pod), nail (longitudinal melanonychia evaluation — Hutchinson sign, asymmetric pigmentation, multiple colors), mucosa (parallel furrow benign on lip and oral, structureless gray on melanoma)
07
Trichoscopy (hair scalp dermoscopy): yellow dots (alopecia areata), black dots (alopecia areata, dissecting cellulitis), exclamation point hairs (alopecia areata), corkscrew hairs (tinea capitis), comma hairs (tinea capitis), broken hairs (trichotillomania), peripilar sign (androgenetic alopecia), white dots and absent follicular openings (cicatricial alopecia)
08
Inflammoscopy / entomodermoscopy: scabies (delta wing jet sign, burrows), molluscum contagiosum (umbilicated structure with central pore), warts (red dots and globules from elongated papillae), psoriasis (regular dotted vessels, white scales), lichen planus (Wickham striae as white lines)
09
Documentation and patient communication: photograph all suspicious lesions for medical record, explain dermoscopy findings to patient (pattern, suspicion level, recommendation), document algorithm score in chart, schedule follow-up or biopsy as indicated, patient education on self-examination (ABCDE rule, ugly duckling sign), referral to dermatologist for complex cases

Which Department to Visit?

You can visit our Dermatoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.