Complex regional pain syndrome, a neurological condition characterized by chronic pain, affects women 3 times more often than men. The syndrome is more common in the fourth and fifth decades of life.1,2
There are 2 subtypes of CRPS. Type I (also known as reflex sympathetic dystrophy) is more common and occurs following minor trauma without peripheral nerve injury. Type II (otherwise known as causalgia) occurs following more notable trauma with injury to a peripheral nerve.1,6 Onset of symptoms most often is secondary to minor peripheral trauma. More common triggers include soft-tissue injury (40%); fractures and subsequent orthopedic surgery (25%); and visceral lesions, such as myocardial infarction and cerebral vascular accident (12%).5 Regardless of the inciting event, prolonged immobilization of a limb has been identified as an important predisposing factor. One study found that 47% of patients who received a diagnosis of CRPS previously underwent immobilization of the same limb.7
The pathogenesis of CRPS has not been fully elucidated. Possible explanations include central nervous system sensitization to thermal, mechanical, and pain stimuli; sympathetic dysfunction leading to vasomotor, pseudomotor, and trophic changes; and inflammatory cytokine release and microcirculatory dysfunction, causing tissue injury.1,2,6
The diagnosis of CRPS is a based on clinical findings. Using the Budapest Criteria established to define CRPS, a clinical diagnosis can be made when all of the following criteria are met: chronic continuing pain disproportionate to any inciting event; 1 or more reported symptoms from 3 or more of the categories of involvement including sensory, vasomotor, pseudomotor, edema, and motor or trophic; 1 or more sign at the time of evaluation in 2 or more of the categories of involvement including sensory, vasomotor, pseudomotor, edema, and motor or trophic.8 Dermatologic findings are a common presenting feature of CRPS and are included in the Budapest Criteria used for diagnosis. In a retrospective chart review (N=26), researchers found that vascular findings were the most common dermatologic manifestation of CRPS—edema in 58% of patients and erythema in 54%.9 Other common manifestations included dermatitis (35%), erythematous papules (23%), and cutaneous atrophy (23%). Hyperpigmentation, which was present in our patient, was seen in 8% of patients in the chart review.9
Complex regional pain syndrome progresses through 3 stages; dermatologic changes are present in each stage and are more severe in later stages. Stage I lasts 2 or 3 months and is characterized by onset of pain, usually burning type, accompanied by allodynia and hyperalgesia. Early vasomotor and pseudomotor changes, such as erythema and edema, may become apparent.1,2 Stage II lasts 3 to 6 months and is characterized by more severe edema and more obvious trophic changes. Functional limitations, such as limited range of motion and muscle weakness, begin to manifest. Stage III—the final and most severe stage—is characterized by obvious hair, skin, and nail changes, as well as functional limitations.1,2 The waxy thickened skin changes and hyperpigmentation observed in our patient are characteristic of stage III. Furthermore, our patient experienced decreased mobility and limited range of motion secondary to tightening of the skin, a characteristic motor change of late-stage CRPS. Although chronic pain and allodynia are the most common characteristics of CRPS, skin changes also can cause notable distress and early dermatologic manifestations can be a chief concern.
Dermatologic management is focused to address the specific skin changes of CRPS. However, traditional treatment of the common dermatologic findings of CRPS is difficult and often unsuccessful; instead, the most successful treatment of skin findings involves controlling the underlying CRPS.9 Current treatment options include removal of any nidus of tissue trauma, sympathetic neural blockade with a local anesthetic, spinal cord stimulation to interrupt dysregulated sympathetic innervation, and physiotherapy or occupational therapy to desensitize skin.1,10
Given the complexity of CRPS and the variability of its presentation, management of the syndrome and its associated dermatologic conditions often requires interdisciplinary care and coordination of multiple specialties. Dermatologists can play an important role in both identification of CRPS and co-management of affected patients. Early diagnosis of CRPS has been universally identified as a key prognostic factor. For that reason, dermatologists should be aware of CRPS and include the syndrome in the differential diagnosis when presented with severe cutaneous findings following trauma either with or without peripheral nerve damage, suggestive of CRPS.