Microscopic Diascopic Dermoscopy (MDD)
A method for ultra-budget dermoscopy!
Diascopy is old-fashioned bedside examination technique for assessing the blanchability of vascular and other skin lesions. It involves the pressing of a transparent viewing medium, traditionally a glass microscope slide against the skin and direct visualisation to see if blood empties from superficial vessels. As well as being used to assess vascular lesions, it is used to assess for purpura and in granulomatous disease like sarcoidosis and granuloma annulare characteristically produces an "apple jelly" appearance. The application of diascopy with a fluid immersion interface removes surface light scatter, as in contact dermoscopy.
Powerful small hand microscopes are cheaply and widely available, such as this example sold for examining currency to detect forgery. These can be twinned with fluid immersion diascopy to produce dermoscopic like examination and imaging.
Examples of such small microscopes can be found on ecommerce sites such as Amazon and eBay for very low cost – in 2024 as low as £2.99 (€3.40 / $3.84 US)
They offer the magnification and illumination components of dermoscopy.
Microscope slides are widely available in hospital and other healthcare settings and if need to be purchased are very cheap. They can be washed and reused between patients and approximate to 10-20p (€0.12-0.23) each.
Versions of the microscope are available with universal smartphone clips such as this example for as little as £5.99 to make it easier to capture images of the lesions if required.
Additional Features
1. Orange Filter
Some versions of the microscope come with additional features such as this orange filter. The rotating orange plastic can be positioned to cover the LEDs (right image) or reveal them (left image), making the light either warmer or colder. Warmer light is sometimes preferred when examining pigmented lesions.
LED revealed (colder light)
LED covered (warmer light)
2. Ultra-violet LED
Most of the microscopes designed for examining currency (seen below) come with:
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2 white LEDs (left)
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1 ultra violet LED (right)
Most of the time the white LEDs are used for MDD of skin lesions. However, the UV LEDs allow the microscope to be used as a miniature Wood's Light for examination for skin microorganisms. This image shows the pink/orange glow from hair follicles containing the bacterium C. acnes. This then doubles as a budget Wood's Light for detection of infections including tinea, erythrasma and pityriasis versicolor and may be used in confirming the application of a photosensitiser when conducting photodynamic therapy for skin cancer.
Performing MDD
1. Take your glass plate and apply a blob of viscous clear fluid (e.g. alcohol or aqueous gel).
2. Apply the glass plate to the lesion wishing to be examined with the fluid side down making good contact with the skin, but not pressing too hard so as not to blanch vessel structures.
3. Apply your microscope to the glass slide with the white LEDs switched on and visualise your lesion.
4. The smartphone adapted versions make it easier to take MDD photographs of the lesion if required.
Identifying lesions with MDD
Examples of lesions able to be identified with this technique include common benign lesions such as seborrhoeic keratosis and benign angiomas.
Conventional dermoscopic image of a seborrheic keratosis (3Gen Dermlite DL4W)
Conventional dermoscopy of a seborrhoeic keratosis
MDD image of a seborrheic keratosis
MDD image clearly demonstrating milia like cysts and comedo like openings of a classical seborrhoeic keratosis.
Below are two examples of benign angiomas, also referred to as vascular lesions. In both examples below, vascular lacunae are clearly visible with white tram lines in both dermoscopic (left) and MDD (right) images.
Dermoscopic
Dermoscopic
MDD
MDD