Mark Reed, DPM

DABFAS FAPWCA

OC Center for Wound Healing & Foot Care -- Dr. Mark Reed - USC / UCSF

714-528-3668

Podiatry Skin Diseases

Malignant Melanoma

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 lesions 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 planter's warts.  These lesions are the precursor of epidermoid carcinoma. Treatment for these lesions should be through as they are definitely precancerous. 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.

 

Psoriasis

 

Psoriasis is a common, chronic, and recurrent inflammatory disease of the skin. It is characterized by round, reddish, dry scaling patches covered by grayish white or silvery white scales. The lesions have a predilection for the nails, scalp, elbows, shins and feet. On the feet, it can be difficult to distinguish it from athlete's foot, and the nail appearance may be confused with fungal infections of the toenails. The nail appearance does have a unique characteristic; it may have a pitting appearance. A characteristic feature of the condition is pinpoint bleeding when the scaled areas are brushed off. A variant of psoriasis is called pustular psoriasis. This form of the disease is characterized by small pustules or blisters filled with clear or cloudy fluid. This can mimic acute athlete's foot. It characteristically does not itch or burn. It is distinguished from athlete's foot by negative fungal cultures. The picture can become confusing because a secondary fungal infection is possible. In this instance both conditions are present at the same time.

 

Psoriasis can also affect the joints of the feet and lower extremities causing a painful arthritis. X-rays will show characteristic erosions of the bones in the toes. Treatment consists of anti-inflammatory medications, steroids, and other medications specific for the treatment of psoriasis.

 

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 breakdown of small veins in the area and are called Spider Veins; they also pose no health risks.

 

Blisters

 

Blisters form as a result of heat, moisture and friction. Blisters can also form as a result of fungal infections of the skin, allergic reactions or burns. If a patient has diabetes, they should be evaluated by a doctor in a timely fashion. Generally, a person will recognize a burn by association with a specific painful event. People with diabetes may not be able recognize the painful event due to a condition called neuropathy. A doctor should attend to burns. Blisters are due to fungal infection of the skin or to allergic reactions, which will generally occur in clusters and be smaller than blisters caused by friction. They will also often occur in areas of the foot, which are free from friction forces.

 

Blisters should be drained leaving the cover of the blister intact. The area should be protected with a non-stick bandage with mild compression. Ice to "hot spots" can be soothing and reduce the thermal damage to the surrounding area. "Double socking" can prevent blisters associated with athletics. Wearing two pair of socks allows the friction to be absorbed between the socks reducing friction to the skin. A sock has been developed that helps to reduce friction and blistering called the Thro-lo sock. It is useful for athletics and for diabetic patients. They are widely available in athletic shoe and apparel stores. Skin protectant sprays and adhesive gel pads are also available.

 

Abrasions

 

Abrasions to the skin are a result of excessive friction resulting in the partial loss of the epidermis. The area should be cleaned with an antibacterial soap and dressed in a non-stick bandage and a topical antibiotic ointment. It may take several weeks for the area to completely heal. During this period, the area should be protected from shearing forces. Deep abrasions can result in scaring. Any sign of infection should prompt a visit to the doctor.

 

Skin Tears

 

Skin Tears result from a rapid, forceful shear to the skin. Skin tears are most commonly self-inflicted by improperly removing adhesive dressings and tape. Careful counter pressure should be applied to the skin near the adhesive dressing as the dressing or tape is slowly removed. A common misconception is that paper tape will not damage the skin. To the contrary this tape can really stick to the skin and will tear the skin if removed improperly.

 

DISCLAIMER: MATERIAL ON THIS SITE IS BEING PROVIDED FOR EDUCATIONAL AND INFORMATION PURPOSES AND IS NOT MEANT TO REPLACE THE DIAGNOSIS OR CARE PROVIDED BY YOUR OWN MEDICAL PROFESSIONAL. This information should not be used for diagnosing or treating a health problem or disease or prescribing any medication. Visit a health care professional to proceed with any treatment for a health problem.
Share by: