Pediatric Annals

Case Challenges 

A 10-year-old Boy with Severe Pain in the Toes

Diala Faddoul, MD

Abstract

Editor’s note:

Each month, this department features a discussion of an unusual diagnosis in genetics, radiology, or dermatology. A description and images are presented, followed by the diagnosis and an explanation of how the diagnosis was determined. As always, your comments are welcome via e-mail at editor@pediatricsupersite.com.

 

The patient is a 10-year-old, previously healthy Hispanic boy who presented with severe pain in his toes for 3 years. The patient described the pain as burning associated with warmth of the toes but no erythema, bluish discoloration, or swelling. He reported that massaging his feet or immersing them in cold water ameliorated his pain slightly.

His review of systems, including other joint aches, blurring in vision, skin changes, headaches, fever, night sweats, weight loss, abdominal pain, and urinary symptoms, was negative. The first time he was seen at our clinic, his parents brought X-rays of his feet, which were taken in Mexico and which were read as normal. As per the patient’s parents, there haven’t been recent stressors, school difficulties, or behavioral problems to explain their son’s severe pain.

Initial workup included erythrocyte sedimentation rate (ESR) (1); CRP (within normal range); ANA (negative); rheumatoid factor (negative); C-anca (< 6) and P-anca (< 6); a complete blood count; and thyroid function tests, all of which were normal (Free T4:1.4). Fasting blood sugar and an oral glucose tolerance test were also ordered. Results were within normal range (fasting sugar: 77; 1-hr glucose level: 66; 2-hr glucose level: 55). The patient was advised to take over the counter non-steroidal anti-inflammatory medications (NSAIDs) and to continue conservative measures.

Over the next few months, his pain became so intolerable that a hospital admission was warranted. A neurologist recommended a nerve conduction velocity testing at that time to rule out peripheral neuropathy. This was again reported as normal. He was discharged on gabapentin, which seemed to improve his pain thereafter.

Erythromelalgia

The patient was finally seen by a rheumatologist, who made the diagnosis of erythromelalgia (EM) based on symptoms, negative workup, and response to gabapentin. This was a diagnosis of exclusion, as so far there is no reported test to confirm it. He continued on gabapentin with improvement in his symptoms to date. His mother reported that as a child, she had the same type of pain, but that her pain slowly improved over the years.

When the patient presented for the first time to our clinic, our differential diagnosis included rheumatoid arthritis; systemic lupus erythematosus; diabetic neuropathy; peripheral neuropathy; psychosomatic pain; Raynaud’s disease; and erythromelalgia (see Sidebar). A rheumatologic disease was ruled out by the negative ANA, C-anca and P-anca and by the absence of other symptoms suggestive of arthritis, such as swelling and stiffness of joints.

Trauma.

Rheumatological diseases (rheumatoid arthrotis, systemic lupus erythematosus, scleroderma, Rayndaud’s disease, erythromelalgia)

Neurological diseases (peripheral neuropathy, diabetic neuropathy)

Psychosomatic.

His fasting blood sugar and 2-hr OGTT were normal, which ruled out diabetic neuropathy. Nerve conduction velocity testing failed to reveal evidence of peripheral neuropathy. Raynaud’s disease presents with cold-induced pain, bluish discoloration, swelling of toes, and improvement of pain with immersion in warm water. Our patient’s pain improved with immersing his toes in cold water. The patient had severe pain in his toes, but no swelling or erythema, which made the diagnosis of erythromelalgia inconclusive initially.

Erythromelalgia is a rare, chronic, debilitating condition characterized by redness, warmth, and severe burning pain of the distal extremities. The feet are more commonly affected than the hands. Pain is precipitated by increases in temperature and by exercise. Patients often obtain relief by immersing the affected extremity in cold water.1 Flaring typically occurs…

Editor’s note:

Each month, this department features a discussion of an unusual diagnosis in genetics, radiology, or dermatology. A description and images are presented, followed by the diagnosis and an explanation of how the diagnosis was determined. As always, your comments are welcome via e-mail at editor@pediatricsupersite.com.

 

The patient is a 10-year-old, previously healthy Hispanic boy who presented with severe pain in his toes for 3 years. The patient described the pain as burning associated with warmth of the toes but no erythema, bluish discoloration, or swelling. He reported that massaging his feet or immersing them in cold water ameliorated his pain slightly.

His review of systems, including other joint aches, blurring in vision, skin changes, headaches, fever, night sweats, weight loss, abdominal pain, and urinary symptoms, was negative. The first time he was seen at our clinic, his parents brought X-rays of his feet, which were taken in Mexico and which were read as normal. As per the patient’s parents, there haven’t been recent stressors, school difficulties, or behavioral problems to explain their son’s severe pain.

Initial workup included erythrocyte sedimentation rate (ESR) (1); CRP (within normal range); ANA (negative); rheumatoid factor (negative); C-anca (< 6) and P-anca (< 6); a complete blood count; and thyroid function tests, all of which were normal (Free T4:1.4). Fasting blood sugar and an oral glucose tolerance test were also ordered. Results were within normal range (fasting sugar: 77; 1-hr glucose level: 66; 2-hr glucose level: 55). The patient was advised to take over the counter non-steroidal anti-inflammatory medications (NSAIDs) and to continue conservative measures.

Over the next few months, his pain became so intolerable that a hospital admission was warranted. A neurologist recommended a nerve conduction velocity testing at that time to rule out peripheral neuropathy. This was again reported as normal. He was discharged on gabapentin, which seemed to improve his pain thereafter.

Diagnosis

Erythromelalgia

The patient was finally seen by a rheumatologist, who made the diagnosis of erythromelalgia (EM) based on symptoms, negative workup, and response to gabapentin. This was a diagnosis of exclusion, as so far there is no reported test to confirm it. He continued on gabapentin with improvement in his symptoms to date. His mother reported that as a child, she had the same type of pain, but that her pain slowly improved over the years.

Discussion

When the patient presented for the first time to our clinic, our differential diagnosis included rheumatoid arthritis; systemic lupus erythematosus; diabetic neuropathy; peripheral neuropathy; psychosomatic pain; Raynaud’s disease; and erythromelalgia (see Sidebar). A rheumatologic disease was ruled out by the negative ANA, C-anca and P-anca and by the absence of other symptoms suggestive of arthritis, such as swelling and stiffness of joints.

Sidebar.

Differential Diagnosis for Toe Pain

  1. Trauma.

  2. Rheumatological diseases (rheumatoid arthrotis, systemic lupus erythematosus, scleroderma, Rayndaud’s disease, erythromelalgia)

  3. Neurological diseases (peripheral neuropathy, diabetic neuropathy)

  4. Psychosomatic.

His fasting blood sugar and 2-hr OGTT were normal, which ruled out diabetic neuropathy. Nerve conduction velocity testing failed to reveal evidence of peripheral neuropathy. Raynaud’s disease presents with cold-induced pain, bluish discoloration, swelling of toes, and improvement of pain with immersion in warm water. Our patient’s pain improved with immersing his toes in cold water. The patient had severe pain in his toes, but no swelling or erythema, which made the diagnosis of erythromelalgia inconclusive initially.

Erythromelalgia is a rare, chronic, debilitating condition characterized by redness, warmth, and severe burning pain of the distal extremities. The feet are more commonly affected than the hands. Pain is precipitated by increases in temperature and by exercise. Patients often obtain relief by immersing the affected extremity in cold water.1 Flaring typically occurs late in the day and continues through the night, impairing sleep.2 The intensity of the symptoms varies greatly from person to person. Less frequently, erythromelalgia may also appear on the face, ears, knees, or other parts of the body.

Erythromelalgia can be primary or secondary. Primary erythromelalgia begins spontaneously at any age. Secondary erythromelalgia has been reported with many disorders but most often with polycythemia, thrombocythemia, neuropathies, and autoimmune diseases. The onset of erythromelalgia may be gradual, with some cases remaining mild and unchanged for decades, or may begin acutely, spreading or becoming disabling within weeks.3

Until recently, erythromelalgia has been a clinical description, with no definite underlying pathophysiology. In a recent article published by Han et al., autosomal dominant EM in which patients experience severe burning pain in the distal extremities in response to mild warmth or exercise has been directly linked to gain-of-function mutations of sodium channel Nav1.7.3

The pain is often refractory to treatment and, at times, multiple medications have to be used to achieve symptom relief.2 Some of these treatments include biofeedback and hypnosis; topical creams (capsaicin cream or Emla cream); oral medications, including aspirin (mainly if erythromelalgia is secondary to thrombocythemia, polycythemia, or other blood dyscrasias); serotonin reuptake inhibitors (sertraline); tricyclic antidepressants (amitryptiline); anticonvulsants (gabapentin2 and carbamazepine); calcium channel blockers; beta blockers; and intravenous medications, including nitroprusside infusions, lidocaine infusions,1 and prostaglandin infusions. Our patient seemed to respond well to gabapentin.


References

  1. Nathan A, Rose JB, Guite JW, Hehir D, Milovcich K. Primary erythromelalgia in a child responding to intravenous lidocaine and oral mexiletine treatment. Pediatrics. 2005;115(4):e504–e507 doi:10.1542/peds.2004-1395 [CrossRef] .
  2. Cohen JS. Erythromelalgia: new theories and new therapies. J Am Acad Dermatol. 2000;43(5 Pt 1):841–847 doi:10.1067/mjd.2000.109301 [CrossRef] .
  3. Han C, Dib-Hajj SD, Lin Z, et al. Earlyand late-onset inherited erythromelalgia: genotype–phenotype correlation. Brain. 2009:132(Pt 7):1711–1722 doi:10.1093/brain/awp078 [CrossRef] .

Sidebar.

Differential Diagnosis for Toe Pain

  1. Trauma.

  2. Rheumatological diseases (rheumatoid arthrotis, systemic lupus erythematosus, scleroderma, Rayndaud’s disease, erythromelalgia)

  3. Neurological diseases (peripheral neuropathy, diabetic neuropathy)

  4. Psychosomatic.

Authors

Diala Faddoul, MD, is a Pediatrician in private practice in Tucson, AZ.

Address correspondence to: Diala Faddoul, MD; e-mail: DialaF@elrio.org.

Dr. Faddoul has disclosed no relevant financial relationships.

10.3928/00904481-20110217-05

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