A 4-year-old girl presented to the office with her mother, who was concerned about a skin problem affecting her heels. According to her mother, the patient’s symptoms were present for six months or more. The child’s symptoms included a severe itch that caused constant scratching, pain and cracking of the skin leading to bleeding. Previous home treatment included the application of various over the counter creams including hydrocortisone, antifungals and hand lotions. These treatments did not help. She had no prior treatment by a physician for this problem. Her past medical history was remarkable for a benign heart murmur and allergic rhinitis. The patient had been tested by an allergist and is reportedly allergic to trees, grass, weed pollens, cats, dogs, dust mites and molds. She had a very mild milk allergy. The remaining review of systems and history were unremarkable. Her mother stated that her child has reached developmental milestones without any delay. This patient was a well-developed, 4-year-old Caucasian female. Her vital signs were normal. Vascular, neurologic and orthopedic exams were unremarkable. The dermatologic exam revealed a symmetrical rash on both heels with dry skin, large flaking scales and deep fissures with evidence of prior bleeding. She also had small skin fissures on the dorsal skin folds of her fingers at the PIP joints. The child had no other rashes. A Guide To The Differential Diagnosis Xerosis of skin is a very common skin disorder, especially in older people. Although one may see xerosis in children, its frequency increases with age. Xerosis, which is also known as asteototic eczema, occurs more frequently in winter months and/or in drier climates. Clinically, the presentation involves dry looking skin, possible fissures and scaling of skin. Other areas of the body such as the lower legs and hands can be affected as well. Certain systemic diseases such as diabetes and hypothyroidism can contribute to xerosis as they can affect vasomotor function to the skin. Xerosis is not caused by a lack of oils in the skin but rather a lack of water. Known irritants would include using salts in the bath, hot water, frequent bathing and harsh soaps. Treatment involves restoring moisture in the skin by drinking plenty of water and using moisturizing creams immediately after the bath or shower. By definition, eczema is the clinical appearance of an inflammatory skin eruption. Oftentimes, clinicians use dermatitis interchangeably. Some clinicians use the term dermatitis for an acute presentation and eczema as a chronic condition. Atopy is associated with asthma, allergic rhinitis, eczema, food allergies, urticaria and elevated IgE levels. Atopic eczema usually develops in childhood. The face is a common initial location of presentation in younger children. Older children will usually have the rash on the flexor surfaces of the arms and legs. When the extremities are involved, it is usually symmetrical. Xerosis of skin is usually associated with atopic eczema. Atopic eczema is known as the “itch that rashes” rather than the rash that itches. Atopy is defined as a tendency to develop certain allergy-related diseases such as asthma, hay fever and eczema. One can perform the atopy patch test to make the diagnosis of atopy by introducing a known allergen to the skin to stimulate an IgE-mediated reaction. Treatment of atopic eczema involves using topical steroid agents for acute flare-ups and using hydrating creams daily for maintenance. Tinea pedis is a fungal infection located on the skin of feet and this is caused by dermatophytes. While tinea pedis is very common in adolescents and older patients, it is uncommon in pre-adolescents. It is uncommon to have the fungal infection on the hands due to environmental reasons. The clinical presentation of tinea pedis may be a wet blistering rash in the acute state or it can be a dry scaling rash. Generally, tinea pedis is asymmetrical with only one foot involved or one foot worse than the other. Web spaces are frequently involved in the acute variety and the periphery of the foot has scaling in chronic conditions. Treatment includes antifungal medications and prevention with hygiene recommendations of maintaining a dry and clean environment for feet in the shoes. Key Insights On Diagnosis And Treatment This patient was diagnosed with atopic eczema. A frank discussion with her mother involved describing the disease process and that this may be a chronic problem. Therefore, even though the initial treatment of implementing a topical steroid medication is fairly straightforward, effective treatment is more involved. First, discuss the allergic component of the disease. Oftentimes when the allergy component is worse (i.e. exacerbation of asthma or allergic rhinitis), then the dermatologic component of eczema may be worse. Proceed to review bathing tips. Recommendations include bathing every day, using mild cleansers such as cetaphil or soaps that are fragrance-free. Other measures include trying to discourage scratching which activates the itch-scratch-itch cycle. When it comes to selecting an appropriate topical steroid medication, mid-level to high potency agents are preferred. Over the counter preparations and low potency steroids do not fare well for treatment of atopic eczema. I will generally use triamcinolone 0.1% ointment (Kenalog, Taro). Ointments are stronger than creams and are made from oils, versus creams, which are oil mixed with water. Ointments are better than creams for dry scaling skin. Discuss the proper usage of topical steroid agents. Application should be a thin coating of medication versus leaving clumps of medication on the skin. Washing hands after handling the medication is important. I will prescribe a small quantity of medication (15 g) so the patient uses the medication sparingly and appropriately. Generally, treatment with the topical steroid will be for two weeks and once the rash is resolved, the patient can subsequently use maintenance creams. Recommendations for maintenance include using a hydrating cream such as eucerin. One should apply it by first pat drying the affected area (never rub skin with a towel) and then rub the cream into the skin within two minutes of getting out of the bath. The patient can use the topical steroid again during acute exacerbations. In Conclusion History is the most important element in unraveling the diagnosis of skin disorders. Studying pictures of rashes and lesions is helpful for recognition of various disorders. However, many skin conditions can have the same features. For example, fine scaling rashes can include tinea pedis, seborrheic keratosis, stucco keratosis, pityriasis alba, psoriasis, lichen planus and cutaneous drug reactions, just to name a few. Considerations in a differential diagnosis should include the characteristics of the rash (symmetry, primary/secondary lesions), color, location and history. In this case, a preadolescent girl with a past medical history of allergic rhinitis and environmental allergies presented with a symmetrical, pruitic skin disorder with xerosis on her heels. Tinea pedis and xerosis are relatively rare in very young children. Dr. Fishco is board-certified in foot surgery and reconstructive rearfoot and ankle surgery by the American Board of Podiatric Surgery. He is in private practice in Phoenix. He is also a faculty member of the Podiatry Institute. For related articles, see “What You Should Know About Atopic Dermatitis” in the September 2005 issue of Podiatry Today. Also check out the archives at www.podiatrytoday.com .