Classical Sweet's syndrome.

A 38-year - old female came to us with sudden eruptions of painful edematous lesions which appeared pseudovesicular on cutaneous examination. Histopathology supported the diagnosis of sweet's syndrome and she responded to a combination of dapsone and oral steroids, after having relapsed on self-discontinuation of monotherapy with dapsone.

CASE REPORT

A 38-year-old female presented with red raised, painful lesions on right forearm with fever since 10 days, which gradually coalesced to form larger lesions [Figure 1]. Patient had similar episodes 3 years back which had subsided on taking some medications. There was a prior history of upper respiratory tract infection. On examination, patient was febrile. A large erythematous plaque of size 8 × 6 cm was present on right upper extremity. Small erythematous plaques were also present on both upper limbs, right side of neck, and chest. Few lesions showed typical “relief of mountain range appearance”. Local temperature was raised in all the lesions. Superficial nerves were not thickened and sensations on the plaques were normal. All other investigations were within normal limits apart from elevated ESR. Histopathology showed a diffuse infiltrate consisting predominantly of mature neutrophils located in the upper dermis without evidence of primary leukocytoclastic vasculitis [Figure 2]. Our patient was initially treated with tablet dapsone 100 mg HS with dramatic early improvement and relapse on discontinuation. The second episode was treated with a combination of dapsone and oral prednisolone started at 30 mg/day and gradually tapered over 4 weeks. The patient is now in remission [Figure 3].

Figure 1

Erythematous tender plaques on forearm with pseudovesicular appearance (Close up - Inset)

Figure 2

Histopathology showed a diffuse infiltrate consisting predominantly of mature neutrophils located in the upper dermis without evidence of primary leukocytoclastic vasculitis

Figure 3

Rapid healing on treatment with Dapsone and oral corticosteroids

DISCUSSION

This condition, originally described by Dr. Robert Douglas Sweet in 1964,[1] is an acute febrile neutrophilic dermatosis, characterized by fever, neutrophilia, erythematous and tender skin lesions that typically show an upper dermal infiltrate of mature neutrophils, with prompt improvement after the initiation of treatment. Classical or idiopathic Sweet's syndrome may be associated with infection (upper respiratory tract or gastrointestinal tract), inflammatory bowel disease, or pregnancy.[2] The lesions have a transparent, vesicle-like appearance secondary to the pronounced edema in the upper dermis (pseudovesicular appearance). Recurrent episodes of Sweet's syndrome occur in one-third to two-thirds of patients.[3] Sweet's syndrome can also present as a paraneoplastic syndrome (most commonly related to acute myelogenous leukemia) or as a medication-related disorder (most commonly after treatment with granulocyte-colony stimulating factor therapy). Cytokines may directly or indirectly have an etiologic role in the development of the dermatosis.

Diagnostic criteria

Improvement in patients with malignancy-associated Sweet's syndrome or drug-induced Sweet's syndrome may occur following successful treatment of the cancer or discontinuation of a causative medication. The therapeutic mainstay for Sweet's syndrome is systemic corticosteroids.[4] Dapsone has been used as either monotherapy or in combination therapy.[5] Other agents used are potassium iodide, colchicine, Indomethacin, clofazimine, cyclosporine, and antibiotics.

Table 1

Diagnostic criteria (Both major criteria and 2 of the 4 minor criteria are required to establish the diagnosis)