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Pigmented Lesions, Pigmented Areas of Skin
Pigmented lesions should always be inspected
and observed. Most pigmented areas are nothing but freckles and moles.
However a potentially deadly pigmented lesion that can occur on the
foot and lower extremity is Malignant Melanoma. A
physician should evaluate any pigmented lesion that suddenly occurs or
a pigmented lesion that starts to change its appearance.
These changes are usually subtle and may consist of increased size and
depth of color, onset of bleeding, seepage of clear fluid, tumor
formation, ulceration and formation of satellite pigmented lesions. The
color is usually not uniform but is likely to be scattered
irregularity, being brown, bluish black or black. An increase in
pigmentation may precede enlargement of the lesion by several months.
Although any part of the body may be affected, the most frequent site
is the foot, then in order of frequency, the remainder of the lower
extremity, head and neck, abdomen, arms and back. Malignant melanoma
may also form under the nails of the feet and hands. The thumb and big
toe are more commonly affected than the other nails. Quite often the
adjacent skin to the nail is ulcerated. Usually a fungal infection
is suspected and antifungal treatment may be administered for months
before the true nature of the lesion is discovered. A black malignant
melanoma of the toe can also be mistaken for gangrene. Overall, the incidence of malignant melanoma is quite low. Actinic Keratosis Another cancer causing lesion that can occur on the feet are called Actinic Keratosis.
Although most commonly found in sun-exposed areas of the body such as
the face, ears, and back of the hands, these lesion can also occur on
the foot. They are characterized as either flat or elevated with a
scaly surface. They can either be reddish or skin colored. On the foot
they are frequently mistaken for plantars warts.
These lesions are the precursor of epidermoid carcinoma. Treatment for
these lesions should be through as they are definitely precancerious.
Treatment consists of freezing the lesions with liquid nitrogen or
sharp excision. Kaposi's Sarcoma Yet another cancerous lesion that can occur on the foot is called Kaposi's Sarcoma.
These lesions occur most commonly on the soles of the feet They are
irregular in shape and have a purplish, reddish or bluish black
appearance. They tend to spread and form large plaques or become
nodular. The nodular lesions have a firm rubbery appearance. The
appearance of these lesions is an ominous sign. In the late 1970's and
early 1980's an outbreak of Kaposi's sarcoma occurred in San Francisco,
California. It was later learned that the disease was associated with
AIDS infection. It can occur without the concurrent AIDS infection but
this is very rare. Chronic athlete's foot
can cause an increased pigmentation to the bottom of the foot. It is
associated with dry scaling skin and may have a reddish appearance. Venous Stasis Generalized
increased pigmentation occurs for a variety of other reasons. Dark
patches of skin occur about the ankles and lower legs in persons who
suffer from Venous Stasis. Venous stasis is caused by an
accumulation of fluid in the lower extremities. This is due to poor
venous return of blood to the heart. Venous blood flow back to the
heart occurs by way of the veins in the feet and legs. Venous stasis is
associated with varicose veins that do a poor job of returning blood to
the heart. As a result the blood flow is slowed, becomes stagnant, and
fluid accumulates in the ankles and lower legs. As the fluid
accumulates in the lower legs, the small and medium-sized veins break
or leak fluid into the tissues. As blood cells break up in the tissue,
they deposit the iron that is part of hemoglobin in the blood cell. The
iron stains the skin causing a light to dark brownish appearance. With
time, the skin and subcutaneous fat becomes thinned and will break down
creating weeping venous stasis ulcerations.
At times, blistering will form with a clear, watery fluid weeping from
the skin. This condition requires professional attention by a physician. Diabetic Dermopathy Another cause of generalized increased pigmentation is diabetes. The condition termed Diabetic Dermopathy
occurs most frequently on the shins and lower legs. They may have the
appearance of small scars. Their appearance may precede the diagnosis
of diabetes by several years. The actual cause of diabetic dermopathy
is not well understood, but it does not cause any particular problem or
pose any particular health threat. Small,
spider-like areas of increased pigmentation on the ankles are caused by
the break down of small veins in the area and are called Spider Veins; they also pose no health risks.
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