An unhealthy gut may lead to an unbalanced gut microbiome. The gut microbiome is made up of trillions of microorganisms that live in your gut. The good bacteria in the microbiome regulates the immune system by producing antiviral proteins that get rid of viruses.
So, when the gut microbiome is unbalanced and has more bad bacteria than good bacteria, the immune response is weakened. The weakened immune response promotes the development of skin issues like acne, eczema and psoriasis.