Analysis of musculoskeletal side effects of oral Isotretinoin treatment: a cross-sectional study

Background/ objectives: Acne vulgaris is a chronic inflammatory disease affecting the pilosebaceous unit. Isotretinoin is an effective treatment option for severe acne. The aim of this study was to evaluate musculoskeletal side effects of systemic isotretinoin treatment.

Methods: Ninety-four patients with acne vulgaris and 100 sex- and age-matched controls were enrolled in this study. Only the patients who had musculoskeletal symptoms were evaluated in this study. All participants were firstly assessed by a dermatologist. The patients were asked whether they had any musculoskeletal symptoms after isotretinoin treatment, if so, the feature and duration of the symptoms were recorded. The dosage of the drug, treatment duration, incidence of arthralgia, myalgia, low back pain, sacroiliitis and tendinopathy and laboratory test results were noted. The severity of pain was assessed by visual analog scale (VAS). The severity of acne vulgaris was evaluated by Global Acne Grading Scale (GAGS). Sacroiliac radiography, magnetic resonance imaging (MRI) and rheumatologic blood tests were requested from the patients meeting Assessment of Spondyloarthritis International Society (ASAS) criteria.

Results: Of the 94 patients, 71 were female and 23 were male. 47.9% of the patients had arthralgia, 53.2% had myalgia, 70.2% (66) had low back pain, 11.7% had sacroiliitis and 4.3% had tendinopathy. 37.8% of 66 patients with low back pain had inflammatory pain and 62.2% had mechanical pain. Bone marrow edema consistent with sacroiliitis was detected by sacroiliac MRI in 11 patients with inflammatory back pain. The median total cumulative dose of isotretinoin was significantly higher in patients with low back pain than in patients without low back pain (p = 0.014). There was no significant correlation between cumulative dose of drug, treatment duration and VAS with ESR and CRP (p > 0.05). Also no correlation was found between GAGS scores and musculoskeletal symptoms (p > 0.05).

Conclusion: Low back pain is one of the very common complications of isotretinoin. It can be mostly mechanical or inflammatory. Isotretinoin-induced low back pain is dose-related, and inflammatory back pain without sacroiliitis is also frequent. The clinicians should be aware of the back pain may be a reflective of sacroiliitis during isotretinoin usage.