Refers to the examination of skin lesions with a dermatoscope.

Consists of a magnifier, a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin.

It allows inspection of skin lesions unobstructed by skin surface reflections.

Modern dermatoscopes use polarised light to cancel out skin surface reflections, rather than a liquid medium.

Polarized light dermatoscopes are useful to dermatologists in distinguishing benign from malignant lesions, especially in the diagnosis of melanoma.

A dermatoscope is composed of a transilluminating light source and a magnifying optic, usually a 10-fold magnification).

There are three main modes of dermoscopy:

Nonpolarized light, contact

Polarized light, contact

Polarized light, noncontact

Polarized light allows for visualization of deeper skin structures,

Non-polarized light provide information about the superficial skin.

Most modern dermatoscopes allow the user to toggle between the two modes.

With specialists trained in dermoscopy, there is considerable improvement in the sensitivity and specificity in diagnosing melanoma compared with naked eye examination.

The accuracy of melanoma diagnosis is increased up to 20% in the case of sensitivity and up to 10% in the case of specificity, compared with naked eye examination.

Increasing specificity reduces the frequency of unnecessary surgical excisions of benign lesions.

The major application of dermatoscopy is for the early detection of melanoma .

Digital dermatoscopy is useful for monitoring skin lesions suspicious of melanoma.

It can help in the diagnosis of skin tumors -basal cell carcinomas, squamous cell carcinomas, cylindromas, dermatofibromas, angiomas, seborrheic keratosis and many other common skin tumors which have typical findings.

Dermoscopy can aid in the diagnosis of scabies and pubic louse, helping identify the location of the mite in the burrow, facilitating scraping of the scabetic burrow.

It can magnify pubic louse, and it allows for rapid diagnosis.

It can aid in the diagnosis of warts.

It can distinguish corn, callouses, trauma, or foreign bodies.

It can in the diagnosis of fungal infections, hair and scalp diseases, such as alopecia areata, female androgenic alopecia, monilethrix, Netherton syndrome, and woolly hair syndrome.

It helps to determine surgical margin of hard to define skin cancers.

Can help differentiate of tinea nigra from malignant melanoma or junctional melanocytic nevus.

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