What Are These Papules?

09/04/2008

Patient Presentation

A 37-year-old woman presented to our clinic with skin-colored papules, which had been present for more than a decade, on the medial aspects of her heels. She complained of intermittent foot pain after prolonged standing. The patient denied any extreme physical activities. Her medical and family histories were non-contributory.

On physical examination, the patient was found to be a healthy, thin woman in no distress. Her feet had numerous, non-tender, soft, compressible, skin-colored to yellow-colored papules and nodules measuring 3 mm to 4 mm on the medial aspects of both feet. (See figure on top.) However, when the patient put weight on the plantar surface of her feet, the lesions increased in size to 5 mm to 6 mm in diameter. (See Figure on bottom.) No other significant physical findings were discovered.

What’s Your Diagnosis?

Physical exertion can cause a host of injuries and patient complaints. Heel pain is a common patient complaint.1,2

However, dermatologic reasons for heel pain are commonly ignored, as the focus tends to be on mechanical or structural problems.2 The patient presented here did have a dermatologic origin of her pain: piezogenic pedal papules.

These lesions were initially de-scribed in 1968 as dermatoceles in a report on a patient with papules along the medial aspect of his heel and complaints of foot pain.3 The papules were then thought of as herniations of fatty tissue through the connective tissue trabeculae of the heel.
 

Epidemiology

There is little agreement about the prevalence of these lesions in the literature.4,5 Numerous authors agree that this often overlooked finding is quite common in the general population, occurring with similar frequency in children and adults.6,7 However, unless these papules are painful, the diagnosis is often overlooked during a regular examination.
 

Clinicopathological Characteristics

On physical examination, the papules are round, skin-colored to yellow-colored, and can be anywhere from 2 mm to 10 mm in diameter. They usually present on the medial aspect of the heel, but have also been found to occur on the wrist and palm.7-10 They usually are asymptomatic but occasionally can become painful. Smaller papules are less likely to become symptomatic than larger lesions.5,9

The size of the papules can vary, as they become visible when the patient stands and tend to diminish when weight is removed from the foot.10 On histology, the papules exhibit degeneration of the trabeculae and septa within the subcutaneous fat, and destruction of the elastic fibers normally present within the overlying dermal connective tissue.9

Etiology

Piezogenic pedal papules have been associated with vigorous physical activity, hereditary factors, repetitive pressure forces in susceptible individuals and collagen defects such as Ehlers-Danlos syndrome.4,5,11,12 The pathogenic mechanism involves degeneration of the septa and trabeculae in the stroma of the connective tissue at the affected site. Subcutaneous fat is then able to protrude through these defects, thereby forming papules.5,9
 

Differential Diagnosis

The differential diagnosis for piezogenic papules includes infantile pedal papules, xanthoma and tophi.

Infantile pedal papules are also known as bilateral congenital adipose plantar nodules, precalcaneal congenital fibrolipomatous hamartomas and pedal papules in the newborn. They present as symmetric, painless, flesh-colored nodules on the medial aspects of an infant’s heels. They appear in the first several months of life and regress by age 2 to 3. In addition to a young age of presentation, infantile pedal papules can also be differentiated from piezogenic papules because the former are accentuated with standing.13

Xanthomas are red-yellow, painless lesions that are most prominent on the buttocks but can occur anywhere. They also may present as sequelae of disorders of lipid metabolism, such as familial hyperlipidemia. Unlike piezogenic papules, their appearance does not change in the weight-bearing state.

Tophi are collections of solid urate that deposit in connective tissues in patients with gout. Common locations include the external ear, foot, hand, prepatellar bursa, and olecranon area. They can be extremely painful and also remain unchanged in the weight-bearing state.14

Management

Treatment for painful piezogenic pedal papules includes simple analgesia, weight loss, use of supportive external pressure devices and taping of the heel. Severe, refractory cases can be treated with surgical intervention.15

Recently, the use of local electro-acupuncture has come to attention, as early studies have shown some success in treating symptomatic patients.16
 

Prognosis

Piezogenic pedal papules are benign skin findings. However, in symptomatic cases, identifying and diagnosing these lesions can greatly improve quality of life. When suspecting this diagnosis, it is vital to examine the patient in a standing position.

Finally, increasing awareness of these lesions is of great importance as it will promote further scientific understanding and exploration of more effective treatments and prophylactic options.