Ectromelia is a congenital condition where long bones are missing or underdeveloped.

Examples include:

- Amelia

- Hemimelia

- Phocomelia

- Sirenomelia

Erythromelalgia is a difficult condition to diagnose as there are no specific tests available. However, reduced capillary density has been observed microscopically during flaring; and reduced capillary perfusion is noted in the patient. Another test that can be done is to have the patient elevate their legs, and note the reversal (from red to pale) in skin color. Tests done at universities include quantitative sensory nerve testing, laser evoked potentials, sweat testing and epidermal sensory nerve fiber density test (which is an objective test for small fiber sensory neuropathy). Due the aforementioned factors, patients may face delays in diagnosis.

Once it has been established that it is not secondary erythromelalgia — see below — a programme of management can be put in place.

Some diseases present with symptoms similar to erythromelalgia. Complex regional pain syndrome (CRPS), for instance, presents with severe burning pain and redness except these symptoms are often unilateral (versus symmetric) and may be proximal instead of purely or primarily distal. Furthermore, attacks triggered by heat and resolved by cooling are less common with CRPS.

Erythromelalgia is sometimes caused by other disorders. A partial list of diseases known to precipitate erythromelalgia is below.

Erythromelalgia can be found in several billing codes systems and other systems. Erythromelalgia is generally classified as a disease of the circulatory system, falling under the class of "other peripheral vascular disease", as the following two billing code systems will show:

ICD-9-CM

According to the ICD-9-CM database (International Classification of Diseases, Ninth Revision, Clinical Modification), Erythromelalgia is listed under Diseases of the Circulatory System and is identified by number 443.82.

ICD-9-CM Diagnosis Codes > Diseases of the circulatory system (390-459) > Diseases of arteries, arterioles, and capillaries (440-449) > Other peripheral vascular disease (443) > Other specified peripheral vascular disease (443.8) > Erythromelalgia (443.82).

ICD-10-CM

According to the ICD-10-CM database (International Classification of Diseases, Tenth Revision, Clinical Modification), Erythromelalgia is listed under Diseases of the circulatory system and is identified by I73.81.

ICD-10-CM Diagnosis Codes > Diseases of the circulatory system (I00-I99) > Diseases of arteries, arterioles and capillaries (I70-I79) > Other peripheral vascular diseases (173-9) > Erythromelalgia (I73.81)

Mesh

According to the MESH database (Medical Subject Headings), Erythromelalgia is classified under the unique ID number of D004916.

OMIM

According to the OMIM database (NCBI - Online Mendelian Inheritance in Man), Primary Erythromelalgia is listed under the number: 133020.