Efficacy of High-Intensity Laser Therapy (HILT) in the Management of Isotretinoin-Induced Sacroiliitis: A Randomized Controlled Trial

Isotretinoin (13-cis-retinoic acid) is a highly effective retinoid derivative of vitamin A, renowned for its use in the treatment of severe, recalcitrant nodular acne. By significantly reducing sebum production, modulating follicular keratinization, and exerting anti-inflammatory effects, it has proven to be a transformative therapy for patients with conditions unresponsive to conventional treatments. However, its potent biological activity is accompanied by a well-documented and diverse profile of adverse effects, ranging from common mucocutaneous symptoms like xerosis and cheilitis to more serious concerns such as teratogenicity, psychiatric effects, and musculoskeletal complaints.

Among these musculoskeletal adverse events, sacroiliitis-the inflammation of one or both sacroiliac (SI) joints-has emerged as a significant, though potentially underrecognized, clinical entity. The sacroiliac joints, which connect the sacrum to the iliac bones of the pelvis, are a primary site for inflammatory processes seen in spondyloarthropathies (SpA) such as ankylosing spondylitis. The presentation of Isotretinoin-induced sacroiliitis often mirrors that of these idiopathic conditions, characterized by insidious-onset lower back pain, buttock pain, and stiffness that may improve with activity and worsen with rest. Morning stiffness is a common feature, and pain can often be referred to the groin or posterior thigh.

The pathophysiological mechanism linking isotretinoin to sacroiliitis remains incompletely elucidated but is a subject of active investigation. Retinoids are known to modulate the immune system, influencing the differentiation and proliferation of various immune cells. It is hypothesized that isotretinoin may disrupt the delicate balance between pro-inflammatory and anti-inflammatory cytokines, potentially triggering an inflammatory cascade in genetically predisposed individuals. This theory is supported by the observation that symptoms often resolve upon discontinuation of the drug and may recur upon re-challenge, satisfying important criteria for a causal relationship.

The clinical significance of this adverse effect lies in its impact on quality of life and the potential for misdiagnosis. The symptomatology can be severe enough to limit daily activities and may be mistakenly attributed to a primary rheumatic disease, leading to unnecessary long-term immunosuppressive therapy if the temporal link to isotretinoin is not identified. Therefore, a high index of suspicion is crucial for dermatologists, rheumatologists, and primary care physicians alike.

Aim: To compare the effectiveness of High-Intensity Laser Therapy (HILT) in reducing pain intensity, in patients diagnosed with Isotretinoin-Induced Sacroiliitis.