PND and Darkness in Corner of my Eyes Near Ethmoid Area. Can It Be Cured?

Im 35 a non smoker,i dont eat dairy or wheat,Ive had post nasal drip for years,constantly have to clear my throat,always have to cough in the morning which clears as the day progresses, and am susceptible to seasonal chesty coughs.Ive a worsening darkness of the skin in the inner portion of my eyes,close to the ethmoid sinus region.Never had any sinus pain or headaches, my ears are fine, but my eyes can get tired and red easily.I have tried anti-histamines,nasal sprays,neti-pot but no joy,help!