A rare case of Acute Febrile Neutrophilc Dermatosis – Sweet’s syndrome

A 32 year old female patient came with chief complaints of red raised painful lesion over the left forearm since 5 days initially smaller in size gradually progressed to the present size within duration of 3-5 days. Patient also gave history of 2 episodes fever prior to the onset of lesion which was moderate grade intermittent not associated with chills and rigors. History of loose stools 2-3 episodes, blood tinged, non-foul smelling 1 week back for which she consulted a local doctor (medication details not known), became asymptomatic within 3days.


INTRODUCTION
In 1964, R. D. Sweet published a description of eight women who presented with erythematous plaques, fever and non-specific infection .The exact etiology of Sweet syndrome is likely to be complex as numerous triggers can impact cell signaling pathways that lead to an increase in neutrophil production and migration into tissues [1]. Acute febrile neutrophilic dermatosis or Sweet syndrome is a condition characterized by fever, tender erythematous papules, nodules or plaques, neutrophilic leukocytosis, and dense dermal inflammatory infiltrates chiefly composed of polymorphonuclear neutrophils [2].

CASE REPORT
A 32 year old female patient came with chief complaints of red raised painful lesion over the left forearm since 5 days initially smaller in size gradually progressed to the present size within duration of 3-5 days. Patient also gave history of 2 episodes fever prior to the onset of lesion which was moderate grade intermittent not associated with chills and rigors. History of loose stools 2-3 episodes, blood tinged, non-foul smelling 1 week back for which she consulted a local doctor (medication details not known), became asymptomatic within 3days. Laboratory investigations are shown in the (Table 1) below revealed Leucocytosis with Neutrophilia, Raised C reactive protein and Raised ESR.

KOH -Negative for fungal elements Chest Xray -Normal USG Abdomen and Pelvis -Normal
On Histopathological examination showed epidermis with mild acanthosis and spongiosis exocytosis of neutrophils into the epidermis. Dermis showed edema and dense neutrophilic infiltrate along with few lymphocytes and occasional eosinophils (Fig. 2). Also seen are perivascular and periadnexal inflammatory cell infiltrate chiefly composed of lymphocytes. No evidence of vasculitis present. Features were suggestive of Neurophilic Dermatoses -Sweet's syndrome (Fig. 3).
Based on clinical and histopathological picture Diagnosis of Sweet's Syndrome -Localised Neutrophilic Dermatosis was made. Patient was treated on Systemic steroids (Prednisolone 0.5mg/kg body weight) and topical steroids with emollients for 2weeks. Later patient was lost to follow up.

DISCUSSION
Sweet's syndrome, or acute febrile neutrophilic dermatosis, is a rare inflammatory condition that is characterized by appearance of abrupt painful papulonodular skin lesion in the setting of a prodrome of fever, leukocytosis with neutrophilia, and pathological findings of neutrophilic infiltration of the upper dermis in the absence of Leukocytoclastic vasculitis. It is considered to be the major prototype of a subset of diseases known as neutrophilic dermatoses and is generally classified into 3 categories of classical (idiopathic), malignancy-associated and drug-induced Sweet's syndrome, all of which share the same presenting scenario of abrupt onset of tender papulonodular skin lesions, most commonly affecting the face, neck, and upper extremities with asymmetrical distribution, in the setting of fever and leukocytosis, with histopathologic findings of dense neutrophilic infiltration of the dermis without evidence of vasculitis [3].   The classical Sweet's syndrome is the most common type, which predominantly affects middle aged women and is usually associated with an infectious process, usually involving the upper respiratory or gastrointestinal tract, inflammatory bowel disease, or pregnancy [4].
The pathogenesis of Sweet's syndrome remains unclear; however, the advances since its recognition have established the role of autoinflammatory processes involving both the innate and adaptive immune systems, eventually leading to their malfunction, resulting in immune-mediated hypersensitivity as well as involvement of cytokines such as interleukin1β (IL-1β), IL-17, and tumor necrosis factor-α (TNF-α) [4].
The classical Sweet's syndrome is the most common type, which predominantly affects middle aged women and is usually associated with an infectious process, usually involving the upper respiratory or gastrointestinal tract, inflammatory bowel disease, or pregnancy. Skin lesion in cases associated with malignancy can be bullous or become ulcerated and resemble those of pyoderma gangrenosum [5]. The most common malignancies associated with Sweet's syndrome are hematological malignancies, most commonly acute myelogenous leukemia. Solid tumors with carcinomas of the genitourinary tract, breast, and gastrointestinal tract have been reported as well. Druginduced form of Sweet's syndrome is most commonly observed with granulocyte-colony stimulating factor, all-trans retinoic acid, trimethoprim-sulfamthoxazole, and azathioprine [4,5].
Diagnosis of Sweet's syndrome is based on typical clinical, laboratory and histological findings. Diagnostic criteria have been formulated to help clinicians to diagnose the disease. According to this criteria, Two major and Two minor criteria need to be fulfilled to make the diagnosis of Sweet syndrome [6]. Usual initial dose is 1mg/kg/day and tapered down over period of 4-6 weeks. Alternatives colchicine, potassium iodide, indomethacin, clofazimine, dapsone, Cyclosporin as secondary line treatment [6].

CONCLUSION
This case was presented to highlight Atypical presentation of sweet syndrome -Annular morphology and localization of lesions only over left forearm Therefore high index of suspicion is needed for its diagnosis in cases of solitary and isolated presentation along with necessary histopathological and laboratory investigations.

Consent
The examination of the patient was conducted according to the principles of the Declaration of Helsinki.