• An upper respiratory tract infection, such as a chest infection or strep throat
• Blood disorders, especially acute myelogenous leukemia, a cancer of the blood and bone marrow
• Inflammatory bowel disease, such as ulcerative colitis or Crohn's disease
• Bowel or breast cancer
• Pregnancy
• Rheumatoid arthritis
• An injury at the site where the rash appears, such as an insect bite or needle prick
• Certain medications, including nonsteroidal anti-inflammatory drugs (NSAIDs)

The most obvious signs of acute febrile neutrophilic dermatosis are distinctive skin lesions that usually develop according to a specific pattern. Typically, a series of small red bumps appear suddenly on the back, neck, arms and face, often after a fever or upper respiratory infection. The bumps grow quickly in size, spreading into clusters called plaques that may be a centimeter in diameter or larger. The eruptions are tender or painful and may develop blisters, pustules or even ulcers. Lesions may persist for weeks to months and then disappear on their own, without medication. With medical treatment, the skin lesions may resolve in just a few days.

Other signs and symptoms of acute febrile neutrophilic dermatosis may include:

• Moderate to high fever
• Pink eye (conjunctivitis) or sore eyes
• Tiredness
• Aching joints and headache
• Mouth ulcers
• Headache

Sometimes other areas of the body are affected, such as the bones, nervous system, kidneys, intestines, liver, heart, lungs, muscles, and spleen.

• Inflammatory bowel disease
• Infections of the upper respiratory tract, including strep throat, pneumonia and tonsillitis
• Urinary tract infections
• Infections of the liver and gastrointestinal tract
• Certain systemic infections