Diascopy

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Diascopy is a diagnostic technique used in dermatology to examine skin lesions. This method involves pressing a glass slide against the skin to observe changes in the color of the lesion. Diascopy helps differentiate between vascular and non-vascular lesions, as well as between hemorrhagic and non-hemorrhagic lesions.

Procedure

The procedure for diascopy is relatively simple. A clear glass slide or another transparent object is pressed firmly against the skin lesion. The pressure applied helps to blanch the skin, pushing blood out of the superficial vessels. Observations are then made based on the color changes that occur.

Applications

Diascopy is particularly useful in diagnosing:

• Erythema
• Purpura
• Telangiectasia
• Sarcoidosis

Erythema

Erythema refers to redness of the skin caused by increased blood flow in the superficial capillaries. When pressure is applied during diascopy, erythematous lesions typically blanch, indicating that the redness is due to vascular dilation.

Purpura

Purpura are purple-colored spots and patches that occur on the skin, mucous membranes, or organs. These lesions do not blanch under pressure, which helps distinguish them from erythematous lesions.

Telangiectasia

Telangiectasia are small, dilated blood vessels near the surface of the skin or mucous membranes. These lesions usually blanch under pressure, similar to erythema.

Sarcoidosis

Sarcoidosis is an inflammatory disease that affects multiple organs, but primarily the lungs and lymph glands. In dermatology, diascopy can reveal a characteristic "apple jelly" color in sarcoid lesions when pressure is applied.

Advantages

Diascopy is a non-invasive, quick, and cost-effective diagnostic tool. It provides immediate results and can be performed in a clinical setting without the need for specialized equipment.

Limitations

While diascopy is useful for initial assessments, it may not provide definitive diagnoses for all types of skin lesions. Further diagnostic tests, such as biopsy or dermatoscopy, may be required for a comprehensive evaluation.

See also

• Dermatology
• Skin lesion
• Biopsy
• Dermatoscopy