Sweet syndrome,
pyoderma gangrenosum, and
subcorneal pustular dermatosis are neutrophilic
dermatoses - conditions that have an inflammatory infiltrate consisting of mature polymorphonuclear leukocytes. The neutrophils are usually located within the dermis in
Sweet syndrome and
pyoderma gangrenosum; however, in
subcorneal pustular dermatosis, they are found in the upper layers of the epidermis.
Sweet syndrome, also referred to as
acute febrile neutrophilic dermatosis, is characterized by
pyrexia, elevated neutrophil count, painful erythematous cutaneous lesions that have an infiltrate of mature neutrophils typically located in the upper dermis, and prompt clinical improvement following the initiation of systemic
corticosteroid therapy. Classical,
malignancy-associated, and
drug-induced variants of
Sweet syndrome exist.
Pyoderma gangrenosum is characterized by painful, enlarging necrotic
ulcers with bluish undermined borders surrounded by advancing zones of
erythema; its clinical variants include: ulcerative or classic, pustular, bullous or atypical, vegetative, peristomal, and
drug-induced.
Subcorneal pustular dermatosis is an uncommon relapsing symmetric pustular eruption that involves flexural and intertriginous areas; it can be idiopathic or associated with
cancer,
infections, medications, and systemic diseases. Since
Sweet syndrome,
pyoderma gangrenosum, and
subcorneal pustular dermatosis share not only the same inflammatory cell but also similar associated systemic diseases, it is not surprising that the concurrent or sequential development of these neutrophilic
dermatoses has been observed in the same individual. Also, it is not unexpected that several of the effective therapeutic interventions - including systemic drugs, topical agents, and other treatment modalities - for the management of these
dermatoses are the same. The treatment of choice for
Sweet syndrome and idiopathic
pyoderma gangrenosum is systemic
corticosteroids; however, for
subcorneal pustular dermatosis,
dapsone is the
drug of choice. Yet,
tumor necrosis factor-alpha antagonists are becoming the preferred choice when
pyoderma gangrenosum is accompanied by
inflammatory bowel disease or
rheumatoid arthritis.
Potassium iodide and
colchicine are alternative first-line
therapies for
Sweet syndrome and
indomethacin (
indometacin),
clofazimine,
cyclosporine (
ciclosporin), and
dapsone are second-line treatments.
Cyclosporine is effective in the acute management of
pyoderma gangrenosum; however, when tapering the
drug, additional systemic agents are necessary for maintaining the clinical response. In some patients with
subcorneal pustular dermatosis, systemic
corticosteroids may be effective; yet, systemic
retinoids (such as
etretinate and
acitretin) have effectively been used for treating this neutrophilic
dermatosis - either as monotherapy or in combination with
dapsone or as a component of
phototherapy with
psoralen and UVA radiation. Topical agents can have an adjuvant role in the management of these neutrophilic
dermatoses; however, high-potency topical
corticosteroids may successfully treat localized manifestations of
Sweet syndrome,
pyoderma gangrenosum, and
subcorneal pustular dermatosis. Intralesional
corticosteroid therapy for patients with
Sweet syndrome and
pyoderma gangrenosum, hyperbaric
oxygen and
plasmapheresis for patients with
pyoderma grangrenosum, and
phototherapy for patients with
subcorneal pustular dermatosis are other modalities that have been used effectively for treating individuals with these neutrophilic
dermatoses.