What's this lesion called and what's the underlying condition? I'll post the correct answer in a few days!
Correct answer: Indeed, the pustular patch is called a kerion celsi, which is the result of dermatophyte fungi invading dead keratinous structures like the horny layer of the skin, nails and hair. It's sometimes also called 'ringworm infection', because of the often ringed (annular) appaerance of the skin lesions.