Final answer:
Deep layers of the skin affected by necrotizing fasciitis may show necrosis, lack of blood flow, severe pain, bullae, and gangrenous tissue, due to bacteria like S. pyogenes and others that release tissue-damaging toxins.
Step-by-step explanation:
Necrotizing fasciitis (NF), also known as flesh-eating disease, is a severe bacterial infection that spreads rapidly and destroys the body's soft tissue. In the deep layers of the skin, symptoms indicative of NF might include necrosis or death of the skin and surrounding tissue, a lack of blood flow, severe pain out of proportion to the visible injury, and the presence of bullae (fluid-filled blisters) or blackened (gangrenous) tissue. Additionally, signs of systemic illness such as fever, chills, and sepsis might be present. These symptoms occur because NF can involve bacteria such as Streptococcus pyogenes (S. pyogenes), but it can also be caused by other bacterial species like Klebsiella, Clostridium, Escherichia coli, Staphylococcus aureus, and Aeromonas hydrophila. These bacteria release toxins that cause direct tissue damage and a strong immune response, potentially leading to widespread tissue destruction.