Is it really possible to differentiate insect bite-like reaction and nodular variant of eosinophilic cellulitis in a healthy person?

ARTICLE

Auteur(s) : Müge Guler Ozden¹, Levent Yildiz², Fatma Aydin¹, Nilgün Şenturk¹, Tayyar Canturk¹, Ahmet Yaşar Turanli¹

¹Ondokuz Mayıs University, Medical Faculty, Dermatology Department, Kurupelit Samsun, Turkey
²Ondokuz Mayıs University, Medical Faculty, Pathology Department, Kurupelit Samsun, Turkey

Exaggerated insect bite reaction and Wells’ syndrome were considered distinct entities. Recently it has been suggested that there is considerable overlap [1]. We present a patient with an exaggerated insect bite reaction which seems to be an overlapping condition with nodular variant of eosinophilic cellulitis and we suggest that this condition should be named an “insect bite-like reaction”.

A 52-year-old woman was referred to our clinic with a 7-day history of a tender lesion with swelling, erythema and ulceration on her abdomen. The patient complained of reduced appetite, fatigue and myalgia, together with the onset of this lesion. She denied a history of recent travel, contact with animals, trauma or insect bites. Systemic sulbactam-ampicilline was prescribed by her general practitioner had been unhelpful. Dermatological examination revealed an indurated nodule with central ulceration on her right abdominal region. There was no obvious surrounding erythema and the affected area was cool and tender to touch (figure 1A). Microbial swabs from the lesions were negative and tissue culture revealed cutaneous micro flora organisms. Laboratory studies were within normal limits and there was no peripheral eosinophilia. A skin biopsy revealed epidermal spongiosis, intraepidermal multilocate vesicles and dermal inflammatory infiltrate. The dermal infiltrate was angiocentric and interstitial and consisted of lymphocytes, plasmocytes and numerous eosinophil leukocytes. Eosinophil leukocytes infiltrated between dermal collagen fibres and invaded deep dermal and subcutaneous tissue. There were also eosinophils in intraepidermal vesicles. There were no flame figures, histiocytes or multinucleated giant cells in serial sections (figure 1B).

The patient was diagnosed as having an exaggerated insect bite reaction and treated with a 40-mg oral prednisone taper. Her lesion gradually disappeared: pruritus and the surrounding induration decreased within a week. After 6 months follow-up we did not observe any relapse of this lesion, and there was no finding of other haematological disorders.

Exaggerated reactions to insect bites are characteristic of patients with immune suppression and haemoproliferative disorders. “Exaggerated reaction” is defined as a lesion more than 20mm in diameter characterised by induration, erythema and pruritus at the site of a mosquito bite [2]. Recently, it has been suggested that this condition would be better named insect bite-like reaction or eosinophilic eruption of haematoproliferative disease [1]. The term ‘‘insect bite-like reaction’’ was first used by Barzilai et al. [1]. Later, Davis et al. identified eight patients who had CLL and skin lesions suggesting arthropod bites although most patients could not recall having been bitten [3]. Wells’ syndrome has both classical and atypical presentations [4]. Flame figures, while characteristic of Wells’ syndrome, may be scarce and may not be seen at all in very early or resolving lesions. There is a considerable overlap between Wells’ syndrome and exaggerated insect bite reaction [1, 4, 5].

Our patient’s clinical and histological presentation, location and non-relapsing course were consistent with an exaggerated insect bite reaction. The acute onset of the lesion, systemic symptoms and intense eosinophilic infiltrate were also consistent with Wells’ syndrome. We excluded this diagnosis since there was no morphea-like resolution phase and no flame figure. The epidemiology, pathophysiology, clinical presentation, histology and treatment of Well’s syndrome and an exaggerated insect bite reaction are very similar. In addition, there are four reports in the literature with the nodular variant of eosinophilic cellulites, which we suspected in our case [6]. This case underlines the notion that they should be considered as part of a spectrum, characterized by eosinophil overactivity, associated with conditions causing immune dysfunction. We propose that these cases could be renamed “insect bite-like reactions”. This denomination is important since we observed this condition in a healthy person and monitored her carefully in order to detect any haematologic malignancy.

Acknowledgements

References

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3 Davis MD, Perniciaro C, Dahl PR, Randle HW, McEvoy MT, Leiferman KM. Exaggerated arthropod-bite lesions in patients with chronic lymphocytic leukemia: a clinical, histopathologic, and immunopathologic study of eight patients. J Am Acad Dermatol 1998; 39: 27-35.

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5 Aberer W, Konrad K, Wolff K. Wells’ syndrome is a distinctive disease entity and not a histologic diagnosis. J Am Acad Dermatol 1988; 18: 105-14.

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