Even dollar store chains are seeing a pullback in spending as higher prices squeeze more consumers

Dollar Tree is slashing its full-year earnings and sales forecasts as its customers continue to struggle with higher prices and spend less.

Shares tumbled more than 10% before the opening bell Wednesday after hitting a 52-week low on the prior day. Less than a week ago, shares of rival bargain chain Dollar General had their biggest one-day decline ever after a dismal quarter.

Dollar Tree said that it now expects full-year adjusted earnings between $5.20 and $5.60 per share. Its...