Acute febrile neutrophilic dermatosis

In many cases, the cause of acute febrile neutrophilic dermatosis is unknown (idiopathic). But sometimes, it can be a sign of an immune system response to one of the following:

• 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)

Although it can be extremely uncomfortable, acute febrile neutrophilic dermatosis often isn't serious. But in some cases, it can be a warning sign of another health problem. For instance, this condition sometimes develops very early in the course of cancer. It may also occur in conjunction with:

• 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

Acute febrile neutrophilic dermatosis is a skin condition characterized by fever, inflammation of the joints (arthritis), and painful skin lesions that appear mainly on the face, neck, back and arms. Although middle- aged women are most likely to develop this condition, it may also affect men, older adults and even infants. The exact cause of acute febrile neutrophilic dermatosis often isn't known. It is suspected that it can be a reaction of the body to certain exposures (sun), infections ( Streptococcus bacteria, C ampylobacter), or medications (azathioprine, nonsteroidal anti-inflammatory medications). This condition can also occur with some types of cancer and other serious health problems. Most often, it isn't serious and will clear on its own in a few months. Healing is much more rapid; however, with treatment, such as corticosteroid use.

Left untreated, acute febrile neutrophilic dermatosis not associated with a more serious condition may disappear on its own within one to three months. Medications, such as corticosteroids (prednisone or prednisolone), can improve skin lesions and associated symptoms in just two or three days, with the worst of the lesions disappearing within one to four weeks. Doctors usually prescribe systemic corticosteroids (which are taken by mouth) to treat this condition. These medications reduce redness, itching, swelling and allergic reactions.

If an underlying cause can be identified, it should be treated (i.e. surgical removal of solid tumors, treatment of infections, or discontinuation of medications). Successful therapy of the underlying disorder may promote resolution of acute febrile neutrophilic dermatosis and prevent recurrences.

With or without treatment, the lesions rarely leave a mark or scar when they eventually disappear. Even after the lesions have resolved, treatment may continue, as recurrence of the condition is common.