Single Nail Involvement as First Sign of Sweet's Syndrome

ment with oncocarbide and anagrelide. She was also receiving anticoagulant therapy following an episode of pulmonary embolism secondary to deep vein thrombosis 2 years before. Our initial differential diagnosis included an ischemic necrosis and an anticoagulant-induced hematoma. Laboratory tests showed neutrophilia and an increased erythrocyte sedimentation rate. Other blood tests were within the normal value, including antinuclear antibody, extractable nuclear antibody, and anti-double-stranded DNA and coagulation factors. One week later, the patient developed multiple tender, painful, red papules and nodules on the limbs, with a pseudovesicular appearance. Histologic examination of a skin lesion showed a spongiotic epidermis with a dense diffuse infiltrate of neutrophils in the upper dermis ( fig. 2 ). Based on the clinical and histologic findings, we performed a final diagnosis of SS related to the underlying myeloproliferative disorder. The temporal relationship between the involvement of the third right digit and the onset of other skin lesions raised the hypothesis that the former represented the initial presentation of SS. This was confirmed by the prompt improvement of both cutaneous and nail lesions under steroid treatment. Initial lesions of SS appear as asymmetric, painful, red or purple-red papules or nodules. Later lesions of SS have a transparent, vesicle-like appearance because of the pronounced edema in the upper dermis. Differential diagnoses include systemic infections, other neutrophilic dermatoses, and vasculitis. Dear Sir, Sweet’s syndrome (SS) is a neutrophilic dermatosis characterized by fever, peripheral neutrophil leucocytosis, and tender erythematous cutaneous lesions [1] . We describe a peculiar, neverreported, initial localization of SS involving a single phalanx. A 54-year-old female presented with a 5-day history of a bluish swelling of the third right finger ( fig. 1 ). At the time of our clinical consultation, we observed an erythematous, violaceous-based, hemorrhagic, vesicular lesion localized on the distal phalanx of the third digit of the right hand, characterized by the complete involvement of the nail bed. The patient complained of severe pain, fever, and arthralgia, which prompted her to seek medical advice. The patient’s medical history was remarkable for a 3-year history of essential thrombocythemia for which she received treatReceived: June 16, 2016 Accepted: July 5, 2016 Published online: July 26, 2016