Max Stanley Chartrand expounds on the role of
keratin formation on the external ear, and the
sometimes unpleasant follies that result with its
absence. Reader inquiries can be directed to "Contact
Us" or faxed to our Colorado City, CO facility at
719-676-6882.
The Role of Keratin in the External Ear Canal
by Max S. Chartrand, M.A.,
DigiCare Hearing Research & Rehabilitation
The keratin layer of tissue of the external ear
canal is made up of inorganic protein (no
circulatory or neurological system), similar in
chemistry to human hair. It lies across the top of
the ear canal from the aperture of the ear canal all
the way to the tympanic membrane, and has a "shiny"
consistency, often bunching up into "lines", as
underlying tissue grows outward from the tympanic
membrane. Keratin tissues are what shields the ear
canal from bacteria, fungus, yeast, amoeba, and
septic debris, allowing the epithelium, the outer
layer of skin tissue, to maintain proper pH and to
maintain overall external ear health. Hence, keratin
is the protective layer over the skin of the ear
canal, without which the ear canal would be totally
susceptible to invasion, injury, and/or disease.
This layer also shields the sensitive neural
reflexes arising from myelinated and unmyelinated
nerve fibers of Cranial V, VII, IX, X that innervate
the external canal, which can cause complications in
many hearing aid and earmold fittings.
The natural desquamation of tissue in the ear canal
is such that tissue grows outward from near the umbo
(or center point of the eardrum) on out to the
aperture of the ear canal. This natural process
generally takes about three months to travel the
full length of the canal, though migration of
specific cells may be uneven. So, that if one were
to place a piece of sand on the tympanic eardrum
today, about three months from now they will reach
up and with fingertip remove the same piece of sand
in the bowl or concha of the ear. Left undisturbed,
then, healthy ear canals are self-cleaning and wax
impaction is rare.
The sad truth is that keratin (or keratinocytes) in
modern day society gets a short shrift, whether via
personal care habits (Q-tips, boric acid ear drops,
scratching with various objects) or via allopathic
medical treatment (ear cleaning methods, most ear
medications, etc.) Without keratin intact on the
canal, for instance, ceruminous and sebaceous
substances do not form properly into earwax and the
canal’s pH drops. This often leaves the canal dry
with a host of extant skin problems (psoriasis,
eczema, external otitis, contact dermatitis,
allergy, and abnormal cell growth, such as basal and
squamous cell carcinomas). Formation of keratin
requires about 10-14 days for a layer of removed
keratin to replace itself, provided the underlying
skin tissue does not become infected, dry or loses
its essential pH in the meantime. The problem is
that boric or acetic acid or hydrogen peroxide
solutions not only remove keratin and epithelium,
they also dry out the skin, setting the external
meatus up for infection. Furthermore, these acids
inhibit cerumen production, as well as prohibiting
the natural desquamation of tissue and regeneration
of the badly needed keratin. Unfortunately, such
harsh solutions are the mainstay of today's
otopharmacopia. Readers may wish to explore other
more gentle, natural approaches to softening
hardened earwax.
For the reader who desires more in depth information
about the physiology of the external ear, I refer
them to the following sources:
Johnson, A. and Hawke, M., “The nonauditory
physiology of the external ear canal”, from
Physiology of the Ear, eds. Jahn, A.F., and Santos-Sacchi,
J., Raven Press: New York, pp 41-58, 1988.
Chartrand, M.S., “Basic Course in External Ear
Care”, Hearing Library, www.digicare.org, 2002.
Chartrand, M.S. "Observation & Referral: The FDA Red
Flags", Hearing Library,
www.digicare.org, 2002.
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