Q: Every fall or winter when the weather turns cold, I get an itchy (and sometimes painful) rash on my toes. It starts out with a reddish and slightly puffy appearance at the ends of my toes, and this eventually changes into a severely itchy patch of dry skin. I noticed that symptoms start to get worse when I'm outside in cold weather, in addition to when my feet are sweating. What could cause this?
A: An itchy, scaly rash that develops during cold weather months is characteristic of a skin condition known as eczema. Eczema is a general term that refers to a number of skin conditions caused by inflammation in the skin, resulting in a rash. Eczema is defined as an allergic or irritant skin condition, which means that it is not contagious. Factors that may increase susceptibility to eczema include: heredity, allergies, increased stress, and nutritional deficiencies. There are a few different sub-types of eczema, the most well-known being atopic dermatitis, which is an allergic skin condition that frequently affects children.
A couple of your symptoms — the rash being brought on by sweat, and the intense itch — describe features of a type of eczema known as dyshidrotic eczema. Dyshidrotic eczema often affects the toes and fingers, and may first appear as a reddened, slightly swollen patch of skin. The rash can also appear on the palms or soles. This type of eczema is usually brought on or intensified by sweat or excess moisture, and these irritated areas of skin will usually become pruritic (itchy), and may develop small blisters. Sometimes the blisters are deeper in the skin and difficult to see. The rash eventually results in a thickened, scaly patch of skin that may persist if left untreated. If pain or discoloration persists, it may a cold injury known as pernio, which is caused inflammation of the skin and deeper tissues.
What Causes Dyshidrotic Eczema?
Like any form of eczema, there are hereditary factors that create susceptibility to developing it, especially if you have a history of allergies. Other factors include:
- Hyperhidrosis (excess sweating)
- Increased emotional stress
- Increased exposure to moisture, such as frequent hand washing.
- Some people develop dyshidrotic eczema in warm weather, while others develop it in cold weather months.
How is Dyshidrotic Eczema Treated?
Since there are many different skin conditions that can cause a rash, it is best for a physician to evaluate symptoms. Fungal infections, bacterial infections, psoriasis, and allergic contact dermatitis are just a few conditions that may have similar symptoms. Providers that most often treat foot rashes include podiatrists, dermatologists, and primary care physicians.
Treatment may include topical corticosteroid medications to relieve inflammation, an emollient (lotion or cream) to restore moisture balance to the skin, and diphenhydramine (Benedryl) to relieve itch. An important part of treatment will be protecting the skin from excess moisture. Two OTC products that do this well are zinc oxide and lanolin ointment, both usually sold as baby care products. For more information on excess sweating see: Sweaty Feet and Odor.
Using an emollient becomes especially important if the skin becomes scaly or cracked. Skin cracks or fissures can lead to pain and infection. To learn more, including types of products that treat dry skin, see: Coping with Dry, Cracked Feet.
Dockery, DPM, Gary L. and Crawford, DPM, Mary Elizabeth (Ed.). Cutaneous Disorders of the Lower Extremity. Philadelphia: W.B. Saunders, 1997. 152-153.
M. Joel Morse, DPM, and Rhonda Cornell, DPM. Keys to Differentiating Eczematous Eruptions In The Pedal Skin. Podiatry Today. Vol. 22(4); April, 2009. Accessed Dec. 16, 2012.
National Institutes of Health: Medline Plus. Dyshidrotic Eczema. Accessed Dec. 16, 2012.