Dermatoscopy is a widely used non-invasive technique
of producing high quality, magnified pictures of
structures under the skin surface, which the naked
eye cannot see. The technique uses immersion fluids,
or Ifs, to reduce light reflection from the skin
surface because the reflected light interferes with
the images of the skin sub structures. For superior
images it is necessary to have the best application
Dermatoscope application techniques
The total procedure consists of selecting the best
immersion fluid and the best techniques of applying
the IF and the dermatoscope on the skin. Studies have
bee done on volunteers to find the optimal procedure.
The two main criteria for optimizing the procedure
were air inclusion and picture clarity. Air inclusion
refers to air bubbles trapped in the immersion fluid.
The fewer the number of air bubbles the better the
Based on past experience, seven IFs have been selected
for study. Including;
- Physiological water solutions
- Aqueous disinfectant
- Alcoholic disinfectant
- Liquid paraffin
- Ultra sound gel
To investigate the IFs, one IF was used daily on
IF and dermatoscopy application techniques
Next, the study investigated the possible techniques
of applying the IF and the dermatoscope.
Three ways were found to apply IF on the skin. These
- Using an eye dropper to place IF on the skin first
an eye dropper to place IF on the dermatoscope
- Using a plastic misting bottle to spray IF
on the skin
Three ways were also found to apply the dermatoscope
on the skin and these were;
- Placing directly on the skin
- Rubbing on the skin
- Rolling on to the skin
Since for each way to apply the IF there were
three ways to apply the dermatosope, there were
a total of 9 ways to study.
IF selection: The study showed that the alcoholic
IFs had the fewest air bubbles and among them isopropanol
had the least. The study, however, preferred ethanol
over isopropanol since ethanol does not have the latter’s
unpleasant odor and, unlike the alcohol disinfectants,
it evaporates leaving no crystals. Liquid paraffin
had the highest number of air bubbles.
The study found alcoholic IFs unsuitable for use
around the eyes, mucosa, lips, nails and the genitalia
since they produce a burning sensation at these places.
Instead, ultra sound gel was recommended at these
places as being viscous they do not flow. These gels
are recommended for all places where liquids should
not flow as in convex surfaces and papular lesions.
Liquid paraffin was the least preferred IF for the
patients because of its oily feel. They did not mind
the other IFs. Liquid paraffin and ultrasound gels
should be wiped off the skin as they tend to stick
on the skin or stain the clothing.
IF and dermatoscope technique selection: It was found
that, whatever the IF used, the combination of direct
application of IF on the skin by an eye dropper and
the roll-on technique for dermatoscope produced the
least air bubbles.
Spraying IFs produced maximum air bubbles and also
patient discomfort since only alcoholic IFs could
be sprayed, and the alcohol evaporation made the skin
quite cold. Liquid paraffin and ultra sound gel were
too viscous to be sprayed or applied by an eye dropper.
Ultra sound gel was applied direct from the bottle.
Applying the IF directly on the dermatoscope ensures,
unlike in other techniques, that the entire glass
is covered but compared to direct application on the
skin, this procedure produces more bubbles. A quicker
way is to place the dermatoscope directly on the skin
and immediately tak a a photograph but this also produces
many bubbles. Rubbing the dermatoscope after placing
it on the skin squeezes out some air bubbles but not
Picture clarity was the best with alcohol disinfectant,
ethanol and isopropanol, with hardly any difference
between them. Water and aqueous disinfectants gave
good, though not so sharp, pictures. Some ultra sound
gel images were blurred.
Alcoholic IFs because of low viscosity and disinfectant
properties were the best IFs. Though isopropanol had
the least air bubbles, ethanol was preferred because
it has less odor, does not stain and evaporates without
The more viscous ultrasound gels should be used around
the mucous areas, eyes, lips, nails, and genitals
because they don’t flow. Moreover, alcohol produces
burning sensations at many of these places.
The method of direct application of IF on the skin
by an eye dropper combined with the roll-on technique
for dermatoscope application gave the best results.