Infections in the mouth, jaw and face are mostly seen as infiltrates or abscesses with odontogenic cause. With little diagnostic effort we can quickly reach the desired treatment success through a causal therapy. A diagnostic and therapeutic challenge represent atypical disease process, which are located in various medical disciplines and are difficult to assign to an agent. In our case report, we represent a immunocompetent 42-year-old patient with no systemic diseases, which envisioned a massive upper lip swelling with bullous-phlegmonösem appearance. There was a detailed diagnostics and interdisciplinary investigation of the disease, which ultimately led to the diagnosis of kerion celsi. This is the maximum variation of tinea barbae, which is often accompanied by severe infiltration, pustule, abscess formation and hair loss. The disease proceeded despite intravenous and topical treatment with antivirals and antibiotics initially progressive. There were also pronounced thrombophlebitis at various intravenous access points, and an infestation on the right arm. Tropical and rheumatoid diseases were excluded as consultants. A pathology proof was not achieved despite multiple samples were taken. The disease was also assessed from different disciplines (Dermatology, Rheumatology, Internal Medicine) differently. Among systemic and topical antifungal therapy ultimately showed a regressive course and corroborated the diagnosis of kerion celsi. Kerion celsi often complicates diagnostics in oral and maxillofacial surgery. It represents the maximum variation of dermatophytosis and is often accompanied by secondary bacterial infections, and requires a long-term systemic therapy. Keywords: Vasculitis, infection, upper lip swelling, impetigo, erysipelas, pathergy phenomenon, thrombophlebitis, cellulitis, herpes zoster, kerion celsi