b. Drug Particle Size. The size of the particles in the medication is an
important factor in skin absorption. Very little absorption takes place if the particles in
the skin medication are large and insoluble; for example, as in zinc oxide ointment. On
the other hand, a great deal of absorption takes place when a solution such as oil of
wintergreen in olive oil or in a lanolin base is rubbed on the skin.
c. Degree of Skin Hydration.
(1) Medication is absorbed by the skin better if the cornified layer (the top
layer of the epidermis) is moist. Ointments soften the skin by wetting it, thus allowing
the medication in the ointment to be absorbed into the skin easily.
(2) Another way to get moisture into the skin is to use an occlusive dressing
over the skin lesion. An occlusive dressing is a dressing that prevents the loss of
moisture from the skin's surface. This type of dressing can be made by placing an
airtight plastic film (for example: Saran Wrap or Handy Wrap) over the medicated
skin. Moisture is kept in the skin allowing the medicine to be absorbed into the skin. If
a corticosteroid medication has been used, this medication will reduce skin inflammation
faster. The occlusive dressing has kept moisture on the skin as well as prevented the
medication from evaporating.
d. Contact Time. Absorption of medication on the skin is increased if the
medication is in contact with the skin for longer periods of time. Since all disease
organisms are not killed at the same time, there is a gradual decrease in the number of
organisms. The longer the medication is on the skin lesions, the more organisms will be
killed.
e. Degree of Friction. Skin medication can be absorbed better as the degree
f. Skin Temperature. When the temperature of the skin increases, skin
medication is absorbed faster. Also, in many cases heat alone is enough to kill disease
organisms.
g. Epidermal Damage. The epidermal layer of the skin is the protective layer.
Medication applied to an area in which this layer has been damaged means that there is
nothing to keep the medication out; therefore, the medication will be absorbed quickly.
5-4.
CLASSIFICATION OF SKIN LESIONS
Skin lesions can be divided into three types: acute lesions, subacute lesions,
and chronic lesions. While reading about each type of lesion and its general treatment,
remember this rule of thumb: If the lesion is dry, make it wet; if the lesion is wet, make it
dry.
MD0575
5-4