why are you prescribing an ointment?
Ever wonder why
your dermatologist prescribed an eczema medication that comes in
ointment form when you’d really prefer a cream? There is actually a
very good reason. Each dermatologic medication is most effective in
a certain form, e.g., cream, ointment, etc. The following describes
the various forms that dermatological medications may take and the
benefits of each form.
cream consists of two agents, oil and water, that combine to form an
emulsion of oil (50%) in water (50%). This form helps the medication
contained within to penetrate the stratum corneum, the horny outer
layer of the skin.
Commonly used liquids include baths, wet dressings, paints, and gels
that liquefy upon contact with the skin. The tar bath, which is used
to treat eczema and other skin conditions, is a liquid.
Oil is a liquid that cannot be dissolved in water. Oil is often
combined with other ingredients to form oil-in-water agents and
Ointments combine oil (80%) and water (20%). This combination
generally forms a more effective barrier against moisture loss than
creams and lotions so ointments tend to be better moisturizers.
While moisturizing is key to controlling eczema, an ointment may not
always be the form prescribed by your dermatologist because a cream
or other form may more effectively deliver a prescribed medication.
paste combines three agents - oil, water, and powder. By definition, a
paste is an ointment in which a powder is suspended. Pastes are
drying and less greasy than ointments. They make an effective
carrier for some dermatologic medications. A common paste used to
treat eczema contains zinc oxide (a powder), calcium hydroxide
solution, and oil.
A single agent, powder is frequently added to other agents to make
shake lotions and pastes. A common powder prescribed by
dermatologist is zinc oxide. Powders should never be applied to skin
creases when the skin is “weeping” as clumps may form that rub and
irritate the skin, making the condition worse.
lotions are made by combining powder and liquid. As the name
implies, shake lotions must be shaken before being applied.
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developed by the American Academy of Dermatology