GlaxoSmithKline is buying dermatology specialist Steifel for $3.6 billion.

The acquisition, announced just days after the rollout of its HIV joint venture with Pfizer, gives GSK a broadened dermatology portfolio accounting for 8% of the global market, with combined revenues estimated at $1.5 billion, and Steifel’s specialty sales force.

Steifel products include Duac, for acne, Olux E for dermatitis and Soriatane for severe psoriasis, along with 15 products in late-stage development. GSK derm brands include Bactroban, Cutivate and Altabax. The GSK and Steifel brands would be combined in a global specialist group under the Steifel name, led by Steifel chairman and CEO Charles Steifel.

“As part of our strategy to grow and diversify GSK’s business, we are continuing to make new investments through targeted acquisitions,” said GSK CEO Andrew Witty. “This transaction will create a new world-leading specialist dermatology business and re-energize our existing dermatology products.”

On Thursday, GSK and Pfizer announced a deal to combine their HIV businesses into a new company in which GSK will initially hold an 85% equity stake and Pfizer 15%.