Thursday, May 18, 2017
Shoe allergies are a form of dermatitis caused skin contacting allergens (irritants) in shoes and socks. Symptoms include inflammation, burning sensation, blisters, itching, fissuring (cracks in the skin) and sometimes secondary infection. Long term exposure to an allergen may result in the skin becoming thick, red and scaly. The allergic reaction is usually confined to the tops of the foot and toes but can also be found on the sole of the foot, the legs, and the sides of the feet and heels. There are many chemical substances in shoes and socks which cause allergies. Glues (para-tertiary butylphenol formaldehyde resin (PTBP-FR), and colophony); leather chemicals (potassium dichromate); rubber chemicals/accelerators (2-mercaptobenzothiazole (MBT) and thiuram mix chemicals); dyes (particularly PPD) ; and metal components/decorations on shoes (nickel sulphate and cobalt chloride) are all potential sources. There is no mechanism for de-sensitising to rosin. Once the dermatitis appears on the skin, treatment is as for any acute dermatitis/eczema, i.e. topical corticosteroids, emollients, treatment of any secondary bacterial infection.
The best way to avoid allergy is by being aware of products that contain the product. Look for the list of ingredients on the product labels or packaging of all substances you come into contact with, not just the ones you think you might be sensitive to. When this information is not often available on labels you may need to contact the manufacturer of the product or cosmetic for advice. However sensible and practical this advice is, it is often complicated because many of the products go under different names and there is a general lack of product information at the point of purchase. This is more difficult with footwear as the relevant information is rarely displayed.
Most countries now have a system called Material Safety Data Sheet (MSDS). MSDS (Material Safety Data Sheets) system catalogues information on chemicals, chemical compounds, and chemical mixtures. MSDS information may include instructions for the safe use and potential hazards associated with a particular material or product. There is a duty to properly label substances on the basis of physico-chemical, health and/or environmental risk but the MSDS is not primarily intended for use by the general consumer. The focus is primarily on the hazards of working with the material in an occupational setting. When no information available and direct inquiry to the product manufacturer is required.
Colophony (rosin) is the yellow/black sticky sap which comes from pine & spruce tree trunks. When it is distilled it is used to produce turpentine and gum, the latter is widely used in every-day products from personal care and beauty products, topical medications, cosmetics, adhesives and sealants, chewing gum to shoe glue and boot polish. Rosin is also used for its friction-increasing capacity including ballet and flamenco dancers rubbing their shoes in powdered rosin to reduce slippage on stage. Violin and banjo players use it to prevent the bridge from moving during a performance. You will often see clouds of it used by gymnasts and competition weight lifters to improve their grip. The list is almost endless but despite its usefulness Colophony also causes Allergic Contact Dermatitis (ACD) and Occupational asthma. Skin contact in some people causes a dermatitis with the typical symptoms of redness, swelling, itching and fluid-filled blisters. Because of the ubiquitous nature of rosin in our every day lives people with allergies have major challenges trying to avoid contact which often means reading labels very carefully and looking for products which contain the irritant or related chemicals. Rosin is also known by several other names, including: Resin terebinthinae, Tall oil, Abietic acid , Methyl abietate alcohol, Abietic alcohol and Abietyl alcohol.
Footnote If you have any of these symptoms then please consult your physician for assistance.
Shoe allergies: A resource for those who have allergies to their shoes