Comparison Between Isotretinoin, Silymarin and Both in the Treatment of Acne Vulgaris

Acne vulgaris, a common and chronic disorder of the pilosebaceous unit, affects up to 85% of adolescent and young adults. The pathogenesis of acne is multifactorial. Traditionally, four distinct processes were believed to play critical roles: increased sebum production, alteration of keratinization processes leading to comedone formation, follicular colonization by Propionibacterium acnes (P.acnes) and inflammatory mediators around pilosebaceous unit.

Orally administered isotretinoin is currently the only agent that can affect all four main factors implicated in acne.

Serum insulin-like growth factor -1(IGF)-1 is a polypeptide hormone that has effects on sebocyte differentiation and proliferation. It leads to lipogenesis, and synthesis of inflammatory cytokines. IGF-1 also stimulates androgen synthesis leading to overproduction of sebum.

Propionibacterium acnes can increase the release of serum amyloid A1 (SAA1) .There is significant elevation of SAA1 in patients with acne, with a positive correlation with its severity.

Oxidative stress plays a role in the pathogenesis of acne in part due to the generation of reactive oxygen species (ROS) in response to infection by the bacterium Propionibacterium acnes, which colonizes the skin and grows in plugged hair follicles, thus attracting inflammatory cells, mainly neutrophils. These in turn secrete inflammatory mediators and generate ROS, which augments the inflammatory response and tissue damage.

Silymarin, the main active component of milk thistle consists of a mixture of flavonolignans and flavonoid taxifolin. Silymarin acts as a hepatoprotective, anticancer, anti-inflammatory and immunomodulatory agent.

Silymarin acts as a free radical scavenger, stabilizes the plasma membrane and reduces the production of inflammatory mediators produced by P. acnes, and scavenges the released free radicals.