A P P E N D I X D
Foot Care for Diabetics
Although not directly related to the normalization of blood sugars,
this short but important section on foot care has been included because
of the constant danger diabetes can present to the lower extremities.
The incidence of limb-threatening ulcerations in diabetics is very
high, affecting approximately one in six to seven patients. Nonhealing
“diabetic” ulcers are the major cause of leg, foot, and toe amputations
in this country, after traumatic injuries such as those occurring in
motor vehicle accidents. These ulcerations do not occur spontaneously;
they are always preceded by gradual or sudden injury to the skin by
some external factor. Preventing such injuries can prevent their sad
consequences.
Virtually all diabetics who have experienced ongoing higher-than normal
blood sugars for more than five years suffer some loss of sensitivity
in their feet to pain, pressure, and temperature. This is because prolonged
blood sugar elevation can injure and eventually destroy all sensory
nerves in the feet (sensory neuropathy). Furthermore, the nerves that
control the shape of the foot are likewise injured, with a resultant
deformity that includes “claw” or “hammer” toes, high arch,
and prominent heads of bones at the bases of the toes on the underside
of the foot. The nerves that stimulate perspiration in the feet are
also affected. This results in the classic dry, often cracked skin that
we see on diabetic feet. Dry skin is both more easily damaged and slower
to heal than is normal, moist skin, and cracks permit entry of infectious
bacteria.
Long term elevated blood sugar also may cause impairment of circulation
in the major arteries of the legs, as well as in the minor arteries
and small capillary blood vessels that supply the skin of the feet.
In order to heal, injured skin can require fifty times the blood flow
of normal skin. If this increase in flow is unavailable, the injury
will probably deteriorate, becoming gangrenous, and facilitate an infection
that spreads up the leg. This infection may not respond to antibiotics.
Blood circulation to the normal foot can readily increase one hundred
fold, if necessary, in order to conduct the heat of warm objects away
from the skin. Impaired circulation may make this impossible, and the
resultant burn may not even cause pain.
A deformed foot with bony prominences (knuckles of toes, tips of toes,
heels, and metatarsal heads at soles) may be continually rubbed or pressed
by shoes. This foot is frequently unable to perceive the extent of such
pressure and may not heal readily if injured. It can be burned at relatively
low temperatures. Impaired circulation likewise can prevent the warming
of cold feet so that prolonged exposure to cold can cause frostbite.
The following guidelines are therefore essential for all diabetics,
to prevent foot injury and the potentially grave consequences that may
ensue:
• Never walk barefoot, either indoors or out.
• Purchase shoes or sneakers late in the day, when foot size is the
greatest. Shoes must be comfortable at the first wearing and should
not require breaking in. Request shoes with deep, wide toe boxes. Pointed-toe
shoes should not be worn, even if the tips are blunted. Some dress shoes
are now available with wide, deep toe boxes. A number of currently available
brands of athletic shoes and walking shoes are especially accommodating
and even have removable insoles so that orthotics (see below) will fit,
without making the shoe too tight. If necessary, I prescribe orthopedic
or custom oxfords for certain of my patients.
• Inspect the insides of your shoes daily for foreign objects, torn
lining, protruding nails, or bumps. Have them repaired if you find any
of these.
• Don’t wear sandals with thongs between the toes.
• Try to alternate at least two different pairs of shoes every few days.
• Ideally, your feet should be examined daily for possible injury or
signs of excessive rubbing or pressure from shoes—blisters, cracks or
other openings in the skin, pink spots, or calluses. Be sure to check
between your toes. Inspect your soles. If necessary, use a mirror or
ask another person to check them. Contact your physician immediately
if any of these signs are found.
• If the skin of your feet is dry, lubricate the entire foot. Suitable
lubricants include olive oil, any vegetable oil, vitamin E oil, emu
oil, mink oil, and emulsified lanolin. Many oils and lotions that contain
these products as major ingredients are available commercially. Do not
use petroleum jelly (Vaseline), mineral oil, or baby oil, as they are
not absorbed by the skin.
• Do not smoke cigarettes. Nicotine can cause closure of the valves
that permit blood to enter the small vessels that nourish the skin.
• Keep feet away from heat. Therefore no heating pads, hot water bottles,
or electric blankets. Do not place feet near sources of warmth such
as radiators or fireplaces. Baths and showers should feel cool—not even
lukewarm. Temperature should be estimated with your hand or a bath thermometer,
not with your feet. Water temperature should be less than 92°F,
as even this temperature can cause burns when circulation is impaired.
A bath thermometer is suggested.
• Wear warm socks and shoes of adequate size when outside in cold weather.
It is wise for all diabetics to have the circulation in their feet measured
every few years. If circulation is impaired, do not remain in the cold
for more than twenty minutes at a time.
• Do not soak your feet in water for more than 3–4 minutes, even if
so instructed by a physician. This causes macerated skin, which breaks
down more easily and doesn’t heal well. When bathing or showering, get
in, get washed, and get out. Don’t soak. Beware of rain, swimming pools,
and any environment that may wet your feet or your shoes. If you swim
regularly for exercise, before getting in the water, rub petroleum jelly
(Vaseline) on your feet to protect them from the water. After leaving
the water, remove the petroleum jelly with a towel.
• Do not put adhesive tape or other adhesive products like corn plasters
in contact with your feet. Fragile skin might be peeled off when the
tape is removed. When applying a bandage, tape should not be applied
to the skin, but to the bandage only.
• Do not put any medications in contact with your skin that are not
prescribed by your physician. Many over-the-counter medications, such
as iodine, salicylic acid, and corn-removal agents, are dangerous. Iodine
products or hydrogen peroxide should never be applied to wounds even
if so directed by a physician.
• If the skin of your feet is dry, your cardiologist should try to avoid
medicines called beta blockers for hypertension or heart disease, as
these can inhibit perspiration that moistens the feet.
• Do not attempt to file down, remove, or shave calluses or corns. This
is dangerous. The toughened skin of a callus is the body’s way of protecting
against irritation, such as by a shoe that rubs your foot. Filing it
off removes that protection, and in my experience, this is the most
common initial cause of foot ulcers and resultant amputations. Do not
permit podiatrists, pedicurists, or anyone else to do so. If calluses
are present, show them to your physician. Ask her or a podiatrist to
arrange for your shoes to be stretched, prescribe special shoes, or
prescribe orthotic inserts. Your physician may instruct you in the use
of a shoe stretcher or a “ball and ring,” both of which can be ordered
by a shoe repair shop. By eliminating the pressure on your foot, the
callus should resolve over time.
• Do not trim your toenails if you cannot see them clearly. Ask a friend
or relative, podiatrist, or your physician to do this for you. If the
corners of your nails are pointed, you can file them with an emery board
or have someone else trim them.
• If you have thickened toenails, ask your physician to have clippings
tested for fungal infection. If infection is present, he should prescribe
Tincture of Fungoid. This solution must be applied twice daily to the
nails to be effective. It must be used for about twelve months to effect
a cure. It helps to first have thickened nails ground down by a podiatrist,
but she/he must be very careful not to damage skin or nail bed.
• Don’t wear stockings or socks with elastic bands that are tight enough
to cause visible depressions in the skin. Don’t use garters. Don’t wear
socks with holes or that have been darned, have thick seams, or are
so large that they bunch up.
• Phone your physician immediately if you experience any injury to your
foot. I consider even a minor foot injury to be an emergency. Procrastination
can be disastrous.
Put a copy of these instructions in your tickler file so that you can
reread them every few months. Eventually, you should know them by heart.
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