Necrotising fasciitis of the head and neck: A case series from the West of Scotland

Abstract

Necrotising fasciitis (NF) is a life-threatening infection which can affect the skin, subcutaneous tissue, superficial and deep fascia with muscular extension. 1 Predisposing factors include chronic immunocompromised states, such as prolonged corticosteroid use, diabetes mellitus and intra-venous drug use. 1 NF affecting the head and neck region is rare. 1 NF has been documented in patients with dental infections, traumatic neck wounds and deep space neck infections. 1 Periocular NF is very rare, with a rate of 0.24 cases per million per annum. 2 Mortality rates of NF can exceed 50%, with periocular NF mortality ranging from 3% to 10%. 2,3 The pathophysiological mechanism behind NF includes the seeding and proliferation of a bacterial pathogen in the subcutaneous tissue, triggering the release of inflammatory mediators, including toxins and cytokines. 2 This inflammatory cascade results in microthrombi formation heralding ischaemic necrosis of tissue. Severe pain, erythema, bullae formation, and surgical emphysema with systemic sepsis are hallmark features, which should raise suspicion.Four types of NF have been described in the medical literature, with types 1 and 2 the most prevalent. 3 Type 1 NF is a polymicrobial infection usually consisting of mixed anaerobes, and can account for up to 80% of all NF cases. 3 Type 2 usually has a monomicrobial aetiology, with Group A beta-haemolytic Streptococcus (GAS) as the most prevalent pathogen. 3 Type 2 NF accounts for 20%-30% of cases, and can present as aggressive and rapidly progressing. GAS can induce a large inflammatory response with type 2 NF more likely to produce bacteraemia, with streptococcal shock syndrome. 4