Diagnosis: Neutrophilic dermatosis of the dorsal hands
The results of H&E were consistent with neutrophilic dermatosis of the dorsal hands (NDDH). Tissue culture was negative for fungus, bacteria, and atypical mycobacteria, confirming the diagnosis.
NDDH is a neutrophilic dermatosis and considered a localized variant of Sweet syndrome, manifesting on the dorsal hands as suppurative, erythematous to violaceous papules, plaques, or nodules that often undergo necrosis, blistering, and ulceration. The diagnosis can be made clinically, although a biopsy is usually performed for confirmation. It is characterized histologically by a dense dermal neutrophilic infiltrate along with dermal edema.1
The pathogenesis of NDDH is not fully known.2 It is often preceded by trauma and may be associated with recent infection (respiratory, gastrointestinal), inflammatory bowel disease, autoimmune disease (eg, rheumatoid arthritis), or malignancy.1 The most common associated malignancies are hematologic, such as myelodysplastic syndrome, leukemia, or lymphoma, although solid tumors also can be seen.1,3 Therefore, patients who receive a diagnosis of NDDH typically require further work-up to rule out these associated conditions. NDDH is a rare enough entity that incidence/prevalence data aren’t available or likely to be accurate.
The differential includes infection and neoplastic processes
NDDH often is mistaken for an infectious abscess and unsuccessfully treated with antimicrobial agents, such as those commonly used for staphylococcus and streptococcus skin and soft-tissue infections. Thus, wound or tissue culture may be considered to exclude infection from the differential diagnosis. In addition to infectious processes such as sporotrichosis or an atypical mycobacterial infection, the differential includes other neutrophilic dermatoses and neoplastic processes such as lymphoma or leukemia cutis.
Sporotrichosis is caused by Sporothrix schenckii and usually spreads proximally after entering through a wound or cut. Special stains on histology and culture are needed to make the diagnosis.
Continue to: Atypical mycobacterial infections