If the App Store on your iOS device is loading very slowly or is not showing app updates correctly, this quick fix discovered by Zachary Drayer (via AppAdvice) may help solve the the issue. You basically need to refresh your App Store app’s cache, by tapping on any of the tab bar items 10 times, such as Featured, Top Charts, Explore, Search or Updates.
To make this work, make sure you tap on the same item 10 times for the cache to clear. Once done successfully, the app screen will go blank for a few seconds before resetting. The source says that this fix also works in the native Watch and iTunes apps too.
Let us know if this worked for you in the comments section below.