In approx. 15-20% of SWEET'S SYNDROME patients, their condition can be triggered by CANCER, one of the commonest being myelodyplastic syndromes which can progress to acute myeloid leukaemia.
NECROTIZING SWEET'S SYNDROME is a rare variant of Sweet's syndrome that can mimic the neutrophilic dermatosis, pyoderma gangrenosum, or the serious bacterial infection, necrotizing fasciitis.
CASE 1: A 26‐year‐old man with acute myeloid leukaemia (AML) developed possible left lower leg cellulitis (bacterial skin infection) progressing to a large bullous (blister-like) lesion. Antibiotics were ineffective. Skin biopsy was negative for infection, but showed dense dermal neutrophilic infiltrate (white blood cells called neutrophils in tissues), suggesting a neutrophilic dermatosis - pyoderma gangrenosum or atypical Sweet's syndrome/SS (necrotizing Sweet's syndrome/NSS). Intravenous steroids were started and the patient's condition improved.
CASE 2: A 57‐year‐old woman had possible acute leukaemia. She had ulcerative lesions on her right arm and non‐itchy rash on her scalp and left inner thigh. After a week on oral steroids her rash hadn't improved. Tissue culture from the right armpit showed methicillin‐resistant Staphylococcus aureus (MRSA - bacterial infection), and was treated with the antibiotic, daptomycin. Skin biopsy from the right arm showed SS with extensive dermal neutrophilic infiltrate and focal necrosis (NSS). Bone marrow biopsy showed myelodysplastic syndrome (MDS). The patient began therapy for MDS, and the NSS was eventually brought under control with steroids, dapsone and intralesional steroid injections. After three months, she had two well‐healed scars on her right forearm and scattered erythematous papules which were treated with steroid cream.
CASE 3: A 61‐year‐old woman had a one‐week history of fever, fatigue and forearm cellulitis with deep ulceration, consistent with her history of a recent burn wound. Blood tests showed a high white blood cell count, anaemia and low platelets. Bone marrow biopsy showed AML. A right arm skin biopsy showed extensive dermal neutrophilic inflammatory infiltrate and a tissue culture was negative for infection. The patient began AML therapy and oral steroids for SS. Treatment for five days led to improvement of the ulceration. On day 7, she developed painful swelling and tenderness at an intravenous‐line removal site. Imaging revealed soft tissue oedema (excess fluid trapped in tissue). Repeat skin biopsy showed a mixed inflammatory infiltrate with neutrophils and histiocytes, suggesting NSS. Aggressive management was started - intravenous steroids and immunoglobulin,and then dapsone.
ADDITIONAL NOTES.
Necrotizing fasciitis (NF): a rare and serious bacterial infection that affects the superficial fascia – a layer of connective tissue that lies beneath the skin and between the muscles and organs in the body. NF not only causes inflammation and damage to the fascia, but also the tissues next to it. Toxins made by the bacteria then destroy soft-tissue, causing it to die. This is known as soft-tissue necrosis.
NSS: an acute necrotizing form of neutrophilic dermatosis that not only causes skin lesions, the most common symptom of SS, but also affects the deeper tissues and causes soft-tissue necrosis.
Histiocytes: immune cells that alert infection-fighting cells to the presence of foreign material such as bacteria. Histiocytes also 'eat' debris in order to get rid of waste products in the tissues. This is known as phagocytosis.
Paul, S., Jammal, N., Akhave, N., Aung, P. P., Loghavi, S., Jain, N., Garcia‐Manero, G., Borthakur, G., Verstovsek, S., Jabbour, E., Adachi, J., Masarova, L., Daver, N., Ravandi, F. and Pemmaraju, N. (2020) Atypical cases of necrotizing sweet syndrome in patients with myelodysplastic syndrome and acute myeloid leukaemia. British Journal of Haematology, July 19 (Wiley Online Library).
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