The neutrophilic dermatoses

Dermatology Nursing, August, 2008 by David Farhi, Daniel Wallach

Neutrophilic dermatoses (ND) are a group of diseases characterized by the presence of a non-infectious infiltrate of mature neutrophilic leukocytes in the skin (Wallach & Vignon-Pennamen, 2006). The three main other features of ND are (a) the potential occurrence of extracutaneous neutrophilic infiltrates; (b) the frequent association with some peculiar systemic diseases; and (c) the possibility of an overlap between several ND.

The group of ND represents a modern conception encompassing several different dermatoses. The first ND identified was erythema elevatum diutinum in 1894 (Crocker & Williams, 1894). Since then, several other ND have been described, including Sweet's syndrome (or "acute febrile neutrophilic dermatosis"), the prototypic ND. One can expect that others will be individualized in the future. Thus, ND is an evolving concept. The ND are classified according to their clinical and histological characteristics (see Table 1).

It should be emphasized that even though elevated neutrophils (either in tissues or in the blood) are frequently associated with infectious--mostly bacterial--processes, the concept of ND refers to diseases where infections have no recognized direct role. This fact is reflected by three common features ofND: (a) all skin and blood cultures are negative for infectious agents; (b) ND are not contagious diseases; and (c) antibiotics have no effects on the evolution of ND. Nevertheless, it is a repeatedly seen situation that fever, pus (or pustules), and elevated blood neutrophils, which may be variably associated in genuine ND, lead patients to be inadequately treated with antibiotics. Indeed, the first differential diagnoses of ND are bacterial infections.

The mechanism of neutrophilic invasion of skin and other tissues in the absence of infection remains unclear. The infiltrating neutrophils are normal. It is postulated that they are attracted in tissues by inflammatory cytokines and growth factors. As a consequence of the absence of identified pathophysiology, all current treatments are symptomatic and flares may occur upon treatment withdrawal.

In this article the diagnostic aspects of the main neutrophilic dermatoses are reviewed, and the management of affected patients outlined, with a particular focus on the nursing care aspects.

THE MAIN NEUTROPHILIC DERMATOSES

Sweet's Syndrome (SS) Robert Douglas Sweet described this disease in eight women in 1964, under the explicit term "acute febrile neutrophilic dermatosis" (Sweet, 1964). SS is the most frequent of the ND.

Definition. SS is characterized by a superficial dermal neutrophilic infiltrate, typically with an acute course and high fever.

Clinical signs. Dermatologic signs may be preceded by flu-like symptoms, such as fever (up to 40[degrees] C), diffuse pain (myalgias, arthralgia), and general malaise. Dermatologic signs typically include elevated papules, nodules, or plaques, sometimes distributed in an annular fashion (see Figure 1). Lesion size varies from a few millimeters to several centimeters. Main locations are the face, neck, and upper limbs, but SS may involve any body site. Atypical forms include bullous, pustular, hemorrhagic, and/ or ulcerated lesions. Actually, many of these atypical presentations represent overlap syndromes between SS and other ND.

Diagnosis. The diagnosis of SS chiefly relies on the clinical picture and the histopathology of a skin biopsy. Typical SS skin pathology shows an intense infiltration of the superficial dermis by neutrophilic leukocytes, associated with an important edema that may provoke junctional blistering. Dermal vessels are usually normal.

In 20% to 30% of cases, Sweet's syndrome is paraneoplastic, the main associated malignancy being acute leukemia. It is important to rule out such a possibility by blood cell count and appropriate work-up, guided by clinical examination. In rare instances, SS may be drug induced.

[FIGURE 1 OMITTED]

Treatment. Oral steroids, at daily doses of 0.5 to 1 mg/kg are usually rapidly efficient (Cohen & Kurzrock, 2003). Therapeutic successes have been also reported with dapsone and colchicine. For limited forms of SS, topical or intralesional steroids may be used alone or in combination with an oral treatment (Cohen & Kurzrock, 2002).

Pyoderma Gangrenosum (PG)

Pyoderma gangrenosum, one of the most dramatic skin conditions, was described in 1930 (Brunsting, Goeckerman, & O'Leary, 1930).

Definition. PG is characterized by a centrifugal ulceration aggravated by minimal trauma. Histology shows a subacute or chronic deep dermal neutrophilic infiltrate.

Clinical signs. PG typically begins with pustules, which evolve rapidly to a painful deep ulceration that extends in a centrifugal pattern (see Figure 2A) (Callen, 1998). The size of the lesions may vary from 1 cm to more than 20 cm. The boundaries of the ulceration are elevated and violaceous. The inner aspect of the peripheral border is classically undermined by pustules. In general, systemic symptoms (fever, asthenia) are discrete or absent. PG lesions are chiefly located on lower limbs, although PG is an ubiquitous dermatosis.