Erythema Nodosum is an erythematous eruption commonly associated with drug reactions or infection and characterized by inflammatory nodules that are usually tender, multiple, and bilateral.
age, sex, seasonality, etc
PATIENT RISK FACTORS
TISSUE SPECIFIC RISK FACTORS
anatomical (due its structure)
vascular (due to the local circulation)
physiopathological (due to tissue function and activity)
Unusual association between erythema nodosum and autoimmune atrophic gastritis. 2018
We report a case of a 46-year-old woman with a history of autoimmune atrophic gastritis and recurrent erythema nodosum (EN). Laboratory results showed iron-deficiency anaemia, positive antiparietal cell antibodies and marginal deficiency of vitamin B12. Although EN was refractory to general measures (rest and non-steroidal anti-inflammatory drugs) and corticosteroid therapy, it was successfully treated with vitamin B12 supplementation.
Successful treatment of chronic erythema nodosum with vitamin B12.2005
A 38-year-old woman presented with painful lesions on both shins that first appeared a few days earlier. Physical examination revealed multiple red tender nodules on both legs. The patient had been treated with nonsteroidal anti-inflammatory drugs for having a few months without any improvement. The patient was referred to a dermatologist and a rheumatologist, who confirmed our diagnosis of chronic erythema nodosum (EN). She returned to the clinic 3 months later complaining of having numbness in the soles of her feet for a few weeks. Her serum vitamin B12 level was 118 pg/mL (normal range 135 to 911). After 4 weeks of twice weekly injections of vitamin B12 at a dose of 1000 mcg, there was a clear alleviation of the numbness, and the EN completely resolved without evidence of recurrence on follow-up. Because it seems that vitamin B12 caused resolution of EN in this case, we recommend that physicians consider testing for vitamin B12 deficiency in patients with EN.