A Guide To Dry Skin Disorders In The Lower Extremity

M. Joel Morse, DPM

Pertinent Insights On The Relationship Between Footwear And Dry Skin

Unlike any other anatomical area, the feet are subject to much chafing, rubbing and sweating, which can affect the skin surface. Wearing shoes without socks can dry out the feet depending on the material the shoes are made from. Due to body heat and moisture, there is almost always higher heat and humidity inside your shoes. If the shoe material is breathable as in leather, the heat and humidity being pushed out can escape from the shoes and such ventilation keeps your foot dry and comfortable. Non-breathable material such as vinyl blocks the heat and humidity inside. Some people have sweatier feet than others and this will interact with the shoe as well. Sweaty feet actually dry out the skin quicker. Shoes that do not fit as well (flip flops, open backed sandals) produce more friction to dry out the skin.

   However, when dry skin occurs on the feet, the symptoms of discomfort are magnified due to shoe wear, the stretching of the skin on the feet each time we step down and by certain synthetic materials in the socks and shoes that dry the skin out even more. Due to the confining nature of the shoes we wear and the lack of fresh air that hits the skin of the feet due to our socks and shoes, dry feet need specialized care in order to prevent pain. In many cases, shoes we wear can also protect our feet from dry skin and fissures if they fit properly and are made of breathable material.

   Abnormal foot mechanics and deformities cause abnormalities in the way we walk. This subsequently causes certain areas of the feet to bear abnormal amounts of weight, which may result in dry patches, calluses, corns and fissures. Orthotics and wearing correct shoes help to spread out abnormal weight and reduce friction.

   One must remember that the skin of the feet has no oil glands and must rely on the sweat glands to moisturize the skin. Sweat glands operate by secreting a substance comprised mostly of water, sodium chloride and electrolytes. Accordingly, sweat is more “drying” than moisturizing.

   Each of our feet is densely covered with approximately 250,000 eccrine sweat glands, making feet one of the sweatiest places on the body. The lack of oil glands makes preventing dry skin difficult but if we had oil glands on our feet, we would slip and slide with each step we took. Socks absorb sweat and are supposed to prevent blisters. It is known that certain synthetic socks can decrease the temperature of the foot as much as 3º and that is enough to prevent blister formation by limiting sweating. Dry feet are not the same as dry skin of the feet.

   One study looked at fabric softeners and surmised that fabric softeners provide benefits to individuals with dry skin because of the decreased friction of the garments against the skin.12 Since friction results in heat, the heat will dry your feet out faster. It is known that nylon and rayon socks cause dryness to the skin.

   In one study, the prevalence of Type IV hypersensitivity to rubber allergens was evident in patients with stasis eczema and/or venous leg ulcers over an 18-month period.13 Accordingly, vascular hose in some patients may result in a dry, itchy skin response and when not wearing the hose at night, patients must moisturize.

Treatment Tips For Specific Skin Conditions

Stucco keratosis. This is a keratotic papule that is usually present on the distal lower acral extremities of males. Stucco keratosis seems to appear with a higher frequency in males but it is not genetic. The lesion is asymptomatic and patients usually do not complain of having the lesions. The name stucco keratosis derives from the “stuck on” appearance of the lesions. The lesions are usually found in elderly patients. The differential diagnoses are seborrheic keratosis and melanoma.

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