(Adds detail on Commonwealth acquisition, stock reaction)

July 23 (Reuters) - Drugmaker Valeant Pharmaceuticals International Inc reported a better-than-expected quarterly profit, helped by strength in its dermatology business in the United States, sending its shares higher in early trade.

The Canadian company also raised its earnings and revenue forecasts for the year to reflect sales of recently acquired Salix Pharmaceuticals' irritable bowel syndrome drug, Xifaxan.

The U.S. Food and Drug Administration approved Xifaxan, also known as rifaximin, in May. Valeant acquired the drug with its $11 billion purchase of Salix earlier this year.

Valeant said it expects 2015 revenue of $10.7 billion-$11.1 billion, up from its prior guidance of $10.4 billion-$10.6 billion. It also raised its adjusted profit forecast to $11.50-$11.80 per share, from $10.90-$11.20.

Valeant shares were up 3.5 percent at C$323.20 in early trading in Toronto.

The company, under Chief Executive Michael Pearson, has grown rapidly through acquisitions. On Thursday, Valeant said it is acquiring Commonwealth Laboratories Inc's Canadian and U.S. business.

Valeant said last week it would buy Egypt's largest drugmaker, Amoun Pharmaceutical, for about $800 million, which Pearson said was expected to close by the fourth quarter.

"It should be quite accretive," Pearson said of the Amoun acquisition in a conference call with analysts. "We will get some synergies with this deal."

Pearson declined to comment on whether Valeant was interested in the animal health sector following market rumors in late June that the Montreal-area company was looking at animal health company Zoetis.

Pearson, named chief executive in 2008, started snapping up dermatology products such as sunscreen and anti-aging products as part of aggressive revenue growth targets.

The net loss attributable to the company was $53 million, or 15 cents per share, in the second quarter ended June 30, compared with net profit of $125.8 million, or 37 cents per share, a year earlier.

Cash earnings, or profit adjusted for one-time items, was $2.56 per share, above the average analyst estimate of $2.46 per share, according to Thomson Reuters I/B/E/S.

Total revenue rose to $2.73 billion, above analysts' average estimate of $2.54 billion.

(Reporting by Ankur Banerjee and Narottam Medhora in Bengaluru and Allison Lampert in Montreal; Editing by Sriraj Kalluvila and Meredith Mazzilli)