U.S. retailers showed strong sales gains in April as the late Easter spurred sales of candy and clothes, and inflation lifted prices of groceries and gasoline.

Some retailers, including Victoria's Secret parent Limited Brands Inc , also raised their forecast for quarterly earnings.

The Thomson Reuters chain store sales index, which is based on analysts' estimates, calls for an 8.2 percent increase from the 25 retailers it tracks that report monthly sales. That would be on top of the better-than-expected 1.7 percent increase in March. (For a related graphic, see: http://r.reuters.com/puq39r)

The biggest factor boosting sales is Easter, which was on April 24 this year and April 4 last year, moving many holiday-related purchases into March.

Still, with gasoline prices pushing past $4 a gallon in parts of the country and unemployment remaining entrenched, analysts were concerned that sales momentum could slow heading in the next few months when there is no major holiday to spur sales.

I paid $4.45 a gallon today, Patty Edwards, chief investment officer at Bellevue, Washington-based Trutina Financial said on Wednesday. I'll tell you, that is certainly cutting into my Nordstrom fund.

Cooler weather than last year might also have hurt sales, according to business weather advisory firm Planalytics.

Retail chains ranging from discounter Target Corp to upscale department store Nordstrom report sales on Thursday, providing a fresh glimpse at consumer spending, which accounts for about 70 percent of the slowly recovering U.S. economy.

Sales of gasoline helped Costco Wholesale Corp beat estimates, although selling more of it also cuts into the retailer's margins, Edwards noted.

The warehouse club operator's sales at stores open at least a year rose 12 percent in April, besting the analysts' average estimate of 8.9 percent compiled by Thomson Reuters. Same-store sales rose 6 percent, excluding gasoline, while analysts forecast 4.3 percent.

Costco also showed the inflation pressures that are weighing on consumers, not only in higher prices for gasoline, but also for groceries as food companies pass on increased costs of ingredients and transportation.

Fresh food prices were up mid-to-high single digits, for example, the company said.

Costco had the type of April sales performance that captured the very essence of the news flow that dominated during the month: inflation, weak dollar, and a slightly more guarded U.S. consumer, Wall Street Strategies analyst Brian Sozzi said in a research note.

Limited Brands blew through expectations with a 20 percent increase in April sales, compared with the analysts' average estimate of 12.2 percent.

The company, which also owns Bath and Body Works, raised its earnings outlook for the April quarter to a range of 37 to 39 cents a share, excluding items. It had previously expected 26 cents to 31 cents, and analysts on average had forecast 36 cents.

Other retailers that posted April same-store sales that beat analyst expectations included teen apparel retailers Zumiez Inc and Hot Topic , and drugstore chain Walgreen Co .

Stocks have priced in a strong performance in April, with the Standard & Poor's retail index <.RLX> up 15.9 percent since March sales were reported, compared with a 13.6 percent increase in the S&P 500 <.SPX>.

(Reporting by Brad Dorfman, editing by Bernard Orr and Lisa Von Ahn)