Discussion: Retiform purpura involves a complete blockage of blood flow in the dermal and subcutaneous vasculature that results in purpuric lesions with a branched or angulated configuration. Determining the etiology of these lesions represents a major diagnostic challenge. In view of a skin biopsy showing leukocytoplastic vasculitis, positive cryoglobulins in serum, and clinical evidence of purpura, we can therefore conclude that our patient had a diagnosis of cryoglobulinemia. Her cryoglobulinemia was most likely of the mixed type given her negative workup for plasma cell dyscrasias. 10% of the cases of mixed cryoglobulinemia are idiopathic, meaning that the cause of such disease is unknown.
Although our patient did not meet the American College of Rheumatology rheumatoid arthritis (RA) criteria (<6 points), her strongly positive serology for RA correlates with an asymptomatic, autoimmunity phase known as preclinical RA, which has been described extensively in the medical literature. We came to the conclusion that our patient had mixed cryoglobulinemia secondary to preclinical RA, indirectly confirmed by her positive response to immunosuppression.
Conclusions: This case illustrates how characteristic skin lesions can encompass a wide variety of diagnosis requiring a systematic approach for diagnosis. In our case, skin biopsy showing small vessel involvement guided our diagnostic testing approach. Also, this case illustrates the importance of re-testing when a high clinical suspicion, based on history and physical examination, is present. Effective diagnostic testing is of great importance in order to avoid complicated laboratory evaluation, multiple specialist referrals, and delay of treatment.
To cite this abstract:Gonzalez-Bravo, DH; Watts, E; Torres, S; Rivera, JR; Rivera, J . RETIFORM PURPURA: CLASSIC PRESENTATION, DIFFICULT DIAGNOSIS. Abstract published at Hospital Medicine 2017, May 1-4, 2017; Las Vegas, Nev. Abstract 458. Journal of Hospital Medicine. 2017; 12 (suppl 2). https://www.shmabstracts.com/abstract/retiform-purpura-classic-presentation-difficult-diagnosis/. Accessed January 19, 2020.