Which of the following is the most severe form of Diptheria

Ref: Harrisons, 19th ed. pg. 978* Diptheria is a nasopharyngeal and skin infection caused by Corynebacterium diphtheriae. Toxigenic strains of C. diphtheria produce a protein toxin that causes systemic toxicity, myocarditis, and polyneuropathy.* The toxigenic strains cause pharyngeal diphtheria, while the non-toxigenic strains commonly cause cutaneous disease.* Harrisons states: "Respiratory/pharyngeal form of diphtheria is from notiable diseases, while cutaneous diphtheria is NOT"* Most severe form of diphtheria: Laryngeal