Treating A Patient With Bilateral Rashes And Intense Itching On The Top Of The Feet

William Fishco, DPM, FACFAS

A 53-year-old male presented to the office with the chief complaint of a rash on the top of both feet, worse on the right than the left. The duration of symptoms had been more than six months. He related intense itching that required scratching. His wife told me that he would wake her up due to rubbing his feet in bed. His primary care physician prescribed a course of a topical cortisone cream using triamcinolone 0.1%, which helped minimally.

   His past medical history was remarkable for hypertension, dyslipidemia, diet-controlled diabetes and gastroesophageal reflux disease. His daily medications included lisinopril (Prinivil, Merck), atorvastatin calcium (Lipitor, Pfizer) and rabeprazole sodium (AchipHex, Eisai). He denied any medication allergies. He denied any environmental or food sensitivities.

   There was no personal or immediate family history of asthma or restrictive airway disease. Prior surgeries included rotator cuff repair and an appendectomy. His habits were remarkable for current cigarette smoking of half a pack per day (30 pack year history) and alcohol consumption of approximately 14 cans of beer per week. He was married and employed as a maintenance worker. He would wear high top boots to work and sneakers after work. He denied any change in shoe gear during this episode.

   The physical exam revealed an overweight, well-dressed, well-nourished male in no acute distress. The vascular exam revealed strong palpable pulses. Capillary refill was immediate to the level of the toes. The neurologic exam revealed symmetric and equal deep tendon reflexes. No loss of epicritic sensation was present. The orthopedic exam revealed symmetric, pain-free range of motion of the ankle, subtalar and midtarsal joints.

   The dermatologic exam revealed a rash on the dorsal surface of both feet. The right foot had an erythematous base with skin scaling, fissuring and weeping. The left foot had erythema without secondary skin changes. The rash distribution was fairly symmetrical. The features of the rash included intense pruritus leading to lichenified skin, an erythematous base, scaling, fissures, wetness (weeping) and a symmetrical pattern.

Key Questions To Consider

1. What is the most likely diagnosis?
2. What is the differential diagnosis?
3. What are the key characteristics of this condition?
4. What is the treatment?

Answering The Key Diagnostic Questions

1. Lichen simplex chronicus
2. Tinea pedis, psoriasis, contact dermatitis, lichen simplex chronicus and atopic eczema
3. No history of atopy
4. Super high potency topical steroids

Pertinent Insights On The Differential Diagnosis

The differential diagnosis for common rashes with these features includes tinea pedis, psoriasis, contact dermatitis, lichen simplex chronicus and atopic eczema.

   Tinea pedis is one of the most common rashes on the foot. Typical presentations include the acute variety, which is typically wet with vesicles and blisters in the web spaces. Fissuring of skin in the web spaces is common — especially when it is macerated — and typically involves the third and fourth web spaces. The chronic type of tinea pedis is generally dry with scales, fissures and lichenification in a moccasin distribution. Although tinea pedis can occur on the dorsal foot, the most common areas to be affected are toes and the plantar foot. Tinea pedis is less likely than contact dermatitis to be symmetrical.

   Psoriasis is classified as an autoimmune disorder of the skin. Plaque psoriasis is characterized by a silvery scale on an erythematous base. Itching can be severe with psoriasis. The most common areas of the body for psoriasis to occur include the scalp, elbows, knees and back. There can be excoriations and crusting of the primary lesion. Intense scratching can lead to lichenification of skin.

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