what causes styes in eyes

Styes in the eyes are caused by a bacterial infection, typically involving the Staphylococcus bacteria. This infection usually occurs in an eyelash follicle or an oil gland on the eyelid. Factors that increase the likelihood of developing a stye include poor hygiene, rubbing eyes with unclean hands, using expired or contaminated eye makeup, certain skin conditions like rosacea or seborrheic dermatitis, and a weakened immune system. Other contributing factors can include blocked oil glands due to sweat or makeup and improper contact lens hygiene. Styes manifest as painful lumps on the eyelid, either on the outer edge (external stye) or inside the eyelid (internal stye).