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 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 weepingvenous 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 termedDiabetic 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.

Corns and calluses are areas of thick skin that result form excessive pressure or friction over a boney prominence. When these areas develop on the bottom of the foot they are called calluses. When they occur on the top of the toes they are called corns. They can also occur between the toes, the back of the heels and the top of the foot. The thickening of the skin is a normal body response to pressure or friction. Often times they are associated with a projection of bone called a bone spur. Not all areas of thickened skin are corns or calluses. Planter warts, inclusion cysts and porokeratoses also cause a discreet thickening of the skin that resembles corns and calluses.

Calluses

The most common area for the formation of calluses on the bottom of the foot is in the area of the ball of the foot. This is a weight bearing area where the long bones behind the toes called metatarsals, bear the greatest amount of weight and pressure. If one or more of these long bones (metatarsals) is out of alignment then excessive pressure is generated in the area producing a callous. The callused area can be very discreet and have a "core" or they can be more dispersed covering a larger area. These areas can become quite painful as the skin thickens. People who have diabetes are at risk of these areas breaking down producing sores or ulcerations that can become infected. People with diabetes should not try home remedies and should see a doctor for the treatment.

Treatment of Calluses

There are numerous over the counter treatments for corns and calluses. Some of these remedies have an acid in them that burn the callous off. Care should be taken when using these medications. If used incorrectly they can cause a chemical burn to the skin. Additionally these remedies are only temporary because the source of the pressure has not been alleviated. Professional treatment consists of using a special shoe insert called a functional orthotic that corrects foot function. In certain instances surgery may be recommended. Surgery is directed at correcting the alignment of the offending bone. Cutting out the callous will only make the condition worse if the underling boney problem is not corrected. Metatarsal surgery is discussed in another section.

Corns

Corns are areas of thick skin that most commonly occur on the top of the toes. Generally there is an associated hammertoe deformity, which causes the toes to rub on the top of the shoes. Professional treatment is directed at correcting the hammertoe deformity. Small corns can also occur on the side of the little toe next to the toenail. A small bone spur causes this problem. Professional treatment consists of removing the bone spur. Bone spurs also cause corns between the toes.

Soft corns are areas of white moist skin between the toes. They most commonly occur between the fourth and fifth toes. They can be very painful and if not treated can form small ulcerations or sinus tracts that can become infected. Acute athlete's foot can mimic the soft corn. The soft corn is due to an irregularity in the shape of the bone in the fourth or fifth toes.

Treatment of Corns

Home treatment should be directed at reducing the pressure between the toes with cotton or a foam cushion and using an antibiotic ointment to reduce the risk of infection. Over the counter corn removers should never be used in this area because of the risk of increased damage to the skin resulting in infection. Professional treatment consists of removing the irregular shaped bone that causes the development of the corn. Some patients prefer that the doctor simply trim down and pad the calloused areas. This is a common form of treatment in patients with diabetes. See correcting soft corns, removing bone spurs, and hammertoe surgery.

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 in tact. 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 with 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.

Athlete's foot is caused by a fungal infection of the skin on the foot. The majority of these infections are caused by one of three fungal agents called dermatophytes. Athlete's foot is by far the most common fungal infection of the skin. The infection can be either acute or chronic. The recurrent form of the disease is often associated with fungal-infected toenails. The acute form of the infection most often presents with moist, scaling between the toes with occasional small blisters and/or fissures. As the blistering breaks, the infection spreads and can involve large areas of the skin on the foot. The burning and itching that accompany the blisters may cause great discomfort that can be relieved by opening and draining the blisters or applying cool water compresses. The infection can also occur as isolated circular lesions on the bottom or top of the foot. As the skin breaks down from the fungal infection, a secondary bacterial infection can ensue.

Diagnosis

The diagnosis of tenia pedis is generally made based upon the clinical presentation. A definitive diagnosis is made by taking a scraping of the skin and culturing it. It may take up to three weeks for the culture to grow the fungus. In some instances the culture may present a false negative result because the skin scraping was inadequate. Some doctors may perform a KOH prep of a skin scraping. This is examined under a microscope and may reveal elements that can make the diagnosis.

Athlete's Foot Treatment

Treatment should be directed at controlling the fungal infection and treating any secondary bacterial infection with oral antibiotics. Soaking the feet in Epsom salts and warm water is helpful. Wearing sandals to reduce moisture accumulation and heat generated by closed shoes will also help in the control and spread of the infection. Other conditions that mimic acute athlete's foot are contact dermatitis and pustular psoriasis.

The chronic form of athletes foot is a relatively noninflamatory type of infection. It is characterized by a dull redness to the skin and pronounced scaling. It may involve the entire bottom of the foot giving a "moccasin" appearance. It generally does not itch or result in the formation of blisters. This form of the disease frequently has an associated fungal infection of the toenails. There are good topical and oral medications available for the treatment of this condition. There are some less common causes of dry scaling skin on the feet.

There are two types of dermatitis caused by substances coming in contact with the skin: primary irritant dermatitis and allergic contact dermatitis. The primary irritant dermatitis is due to a non-allergic reaction of the skin resulting from exposure to an irritating substance. Allergic contact dermatitis is the allergic sensitization to various substances.

Primary Irritant Dermatitis

People who work in areas where their feet are exposed to repeated or prolonged contact to chemicals, oils, or wet cement can develop primary irritant dermatitis. There are certain solutions that people soak their feet in as home remedies. Some of these solutions are safe if used properly, but their improper use can cause a significant contact dermatitis. This can result in skin break down and infection. This is particularly dangerous in people with diabetes; the result can be devastating and limb threatening. A common misconception is the value of soaking in hot water. Some people believe that the hotter the water the better. Quite to the contrary, hot water can cause damage to the skin and result in first or second-degree burns. People will soak their feet in all sorts of solutions. Common solutions are bleach, vinegar, salt water and iodine-based solutions such as betadine. If used properly and under the guidance of a doctor, these solutions can be beneficial. A common mistake that is made is to create solutions that are too strong. Should this occur, irritation to the skin and the development of a rash can develop. The dermatitis that results can also become secondarily infected.

Allergic Contact Dermatitis

Allergic contact dermatitis is the result of exposure to substances that sensitize the skin, so that each time one becomes exposed to it again, an inflammatory reaction will occur. Some people are allergic to the substances in the dyes of socks or the materials used to make shoes. The rash that develops is in a pattern that reflects the exposure to the substance. Adhesive tapes can cause an allergic reaction with blisters or a rash developing beneath the tape. Not all blistering or rashes from tape on the feet however are an allergic reaction. Because of the heat and the accumulation of moisture beneath the tape an acute athlete's foot infection may occur.

Treatment

Treatment should be directed at the cause of the dermatitis. Burns should not be treated with ointments because ointments are too occlusive and can trap the heat in the burned tissues resulting in further tissue damage. Cool compresses are soothing and can limit the damage caused by the burn. The dermatitis caused by the soaking of the feet in concentrated solutions act like chemical burns and cool compresses are also useful in this instance. Dermatitis caused by an allergic reaction will respond well to topical steroid compounds like hydrocortisone cream. Steroid creams should not be used unless you are certain that the condition is caused by an allergy. Cortisone creams will mask infection and allow infections to get worse while reducing the normal inflammatory reaction associated with infections. Anti-fungal creams are useful in the treatment of athlete's foot that may be caused by occlusion under adhesive tape.

A 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 planters warts. These lesions are the precursor of epidermis 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.