Today, Dr. Heather Wolfe of Firm E with discussant, Dr. Kazi, presented a fascinating case of drug-induced lupus due to minocycline.
The patient was a young, Hispanic woman who presented with two months of myalgias, arthralgias, generalized fatigue, low-grade fevers, and photo-distributed erythematous rash in the setting of one year of taking minocycline for treatment of acne. Her physical examination was notable for mild, photo-distributed erythema but was, otherwise, negative for mucosal ulcers, Raynaud’s phenomenon, synovitis, muscle weakness, sequelae of sicca symptoms, or lymphadenopathy. Laboratory findings were notable for mildly elevated transaminases (AST 87, ALT 106), mild elevation in her total bilirubin (2.2), and an alkaline phosphatase of 153. Her electrolytes were within normal limits. Her white blood cell count was 11.5, hemoglobin 11, and platelets were 152. Her cell differential was within normal limits. She had negative HIV and hepatitis serologies. ESR was 40. Her ANA titer was 1:640 with a homogenous pattern. Complement levels were normal. Double-stranded DNA antibody titer was negative. Anti-histone antibody was negative. Rheumatoid factor and anti-CCP was negative. Because her laboratory findings were inconclusive, the decision was made to stop her minocycline and observe. All of her symptoms had resolved after cessation of minocycline without evidence of recurrence.
- Diagnosis: No definitive criteria or tests. Suggested by (1) positive anti-nuclear antibody, (2) no history of systemic lupus erythematosus prior to the causative agents, (3) use of an implicated agent, (4) rapid improvement of symptoms (within weeks) after discontinuation of implicated drug, and (5) one or more clinical features of SLE
- Implicated agents:
- Laboratory Features:
- Anti-nuclear antibody: >99%
- Anti-histone antibody: Anti-histone antibody profiles and prevalence differs depending on the offending agent. Among the classically described agents (e.g. procainamide, hydralazine, and quinidine), prevalence exceeds 90%. This prevalence can be significantly lower in other drugs. For example, prevalence of positive anti-histone antibody in patients with minocycline-induced lupus, as seen in our patient, can be as low as 13% in some series.
- Anti-double stranded DNA antibody: Typically absent but can be present more often in drug-induced lupus associated with TNF-alpha inhibitors and interferon-alpha
- Complement levels: Typically within reference range, unlike in SLE (as seen in our patient)
- Differences between idiopathic SLE and drug induced lupus: