Dermatology of Systemic Disease

Question 1

Causes of erythema nodosum

Answer 1

NO – idiopathic
D – drugs (penicillin, sulphonamides)
O – OCP/ pregnancy
S – sarcoidosis/ TB
U – UC/ Crohn’s disease/ Behçet’s disease
M – microbiology (streptococcus, mycoplasma, EBV + more)

Question 2

5 features of erythema nodosum

Answer 2

Inflammation of subcutaneous fat
Tender, erythematous, nodular lesions
Often shins, may occur elsewhere (e.g. forearms, thighs)
Usually resolves < 6 weeks
Heal without scarring