Answers

What does the image show? Livedo reticularis 

What should you do next? Further testing and antibiotics. See Discussion and table below. 

Discussion

Livedo reticularis is a rare skin condition caused by stagnation of blood within dilated capillaries causing a lacy, nonraised pink/purple net-like blotchy skin discoloration. In itself it is not dangerous, but the etiology should be determined as many causes are potentially dangerous.

Etiologies of livedo reticularis can be classified into idiopathic, vasoconstrictive, obstructive, and vasculitic, with the latter two categories being the ones to worry about.  In this case, the cause was determined to be cryoglobulinemia, thought to be resulting from mycoplasma pneumoniae. See the table for additional obstructive and vasculitic causes.

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This patient’s livedo reticularis resolved with antibiotics to treat her infection.

Table 1: Livedo reticularis

Pathology Stagnation of blood within dilated capillaries
Appearance Lacy, nonraised, net-like red to purple blotches and rings with central clearing
Etiologies Idiopathic, vasoconstriction, obstruction, and vasculitis (see below)

Obstructive

Antiphospholipid antibody syndrome, arterial injection, hypercalcemia, cholesterol emboli, polycythemia, essential thrombocytopenia, cryoglobulinemia

Vasculitic

Lupus, polyarteritis nodosa, rheumatoid arthritis, tuberculosis, pancreatitis, dermatomyositis, lymphoma 

Brady Pregerson, MD, is an emergency physician at Cedars-Sinai Medical Center in Los Angeles and at Tri-City Medical Center in Oceanside, California.

Reference

Pregerson B. Emergency Medicine1-Minute Consult Pocketbook. 5th ed. EMresource.org; 2017. 

This article originally appeared on Clinical Advisor