Case of the Month

Answer to July’s Case of the Month...

A. Wells’ syndrome

The images indicate a diagnosis of Wells’ syndrome (also known as eosinophilic cellulitis). This rare inflammatory skin condition is thought to be a nonspecific hypersensitivity reaction to exogenous or endogenous stimuli, such as arthropod bites, infections or infestations, drugs, or immunization (1).

It typically appears as a sudden onset of large, well-circumscribed, edematous erythema  located on extremities or trunk that may have an annular configuration and are usually pruritic or painful. Over a period of days, edematous and erythematous lesions evolve into plaques with violaceous borders. Lesions resolve without scarring, usually within weeks to months, but multiple recurrences are common (2). The histological pattern is characterized by dermal edema, diffuse dermal eosinophilic infiltrates, histiocytes, and flame figures (3). The flame figures are distinctive, but not specific for Wells’ syndrome, and can be seen in other eosinophil-rich disorders. The diagnosis of Wells’ syndrome should be based on the clinical presentation, course of the disease with its recurrences, and histopathology findings.

Ofuji disease (eosinophilic folliculitis) is a rare, noninfectious inflammatory dermatosis characterized by clusters of erythematous papules and pustules predominantly involving the face, where the lesions tend to present as an annular or arcuate configuration with central clearing and centrifugal extension. It may also affect the trunk, the extremities, and the scalp (2). Histopathology shows infiltration of eosinophils into hair follicles and perifollicular areas, sometimes with follicular damage. The infiltrates also may contain lymphocytes and neutrophils, and may be perivascular as well as follicular (2).

Angiolymphoid hyperplasia with eosinophilia (epithelioid hemangioma) is a rare vascular disorder that shows a predilection for the head and neck area, including the ears, and is characterized by intradermal or subcutaneous reddish-brown papules and/or nodules. Lesions may be associated with pruritus or pain, or may pulsate (4). Histologically, it is composed of a proliferation of vascular channels with a surrounding infiltrate of lymphocytes, macrophages, and eosinophils (2).

Tungiasis presents clinically as erythematous papules, usually on the feet and the legs, that slowly enlarge over a few weeks to 4–10 mm in diameter. A fully developed white or yellowish, firm, somewhat translucent nodule may be painful. Dermoscopy facilitates visualization of ovoid eggs, and thus the diagnosis of tungiasis. Histopathology demonstrates the dense superficial and deep perivascular and interstitial mixed-cell infiltrates with numerous eosinophils (5).

Allergic contact dermatitis (ACD) is due to skin contact with an environmental allergen that causes delayed hypersensitivity reaction with itching or burning. The clinical manifestation of ACD is eczematous dermatitis characterized by pruritus, erythema, edema, and vesicles usually confined to the area of direct exposure. The hands, feet, and face (including the eyelids) are common sites for ACD (2). Histopathology demonstrates dermal spongiosis (often with vesicles) at different levels of the epidermis, exocytosis of lymphocytes and eosinophils, and microabscesses (6).

References

1. AC Katoulis et al., “Idiopathic bullous eosinophilic cellulitis (Wells’ syndrome)”, Clin Exp Dermatol, 34, e375 (2009). PMID: 19489853.
2. LM Leiferman, MS Peters, “Eosinophils in Cutaneous Diseases”, Fitzpatrick’s Dermatology in General Medicine, 8^th edition. McGraw-Hill Education: 2012.
3. M Moossavi, DR Mehregan, “Wells’ syndrome: a clinical and histopathologic review of seven cases”, Int J Dermatol, 42, 62 (2003). PMID: 12581147.
4. KG Effat, “Angiolymphoid hyperplasia with eosinophilia of the auricle: progression of histopathological changes”, J Laryngol Otol, 120, 411 (2006). PMID: 16696882.
5. J Heukelbach, “Tungiasis”, Rev Inst Med Trop Sao Paulo, 47, 307 (2005). PMID: 16553319.
6. RL Rietschel, JF Fowler, “Histology of Contact Dermatitis”, Fisher’s Contact Dermatitis, 6^th edition, 35–37. PMPH-USA: 2008.

Follow-Up Question

Which of the following is most likely to be present in flame figures of Wells’ syndrome?

a. Mucopolysaccharide
b. DNA
c. Damaged collagen fibers
d. Lipid

Follow-Up Answer

B. DNA

Recently, mesh-like structures have been identified in flame figures that stain positively with propidium iodide, indicating the presence of DNA (1). The origin of the DNA is most likely nuclear due to strong immunoreactivity flame figures show for histone H2A. In addition, histone H2 is the third most abundant protein within flame figures assessed by mass spectrometry (1). Extracellular histones, concentrated in DNA traps, are toxic to host cells. There is no mucopolysaccharide or lipid present in flame figures. They are composed of eosinophil granule major basic protein (bone marrow proteoglycan) encrusted on collagen fibers in the dermis.However, the compositing of collagen is normal, suggesting that an initial degeneration of collagen is not a factor in initiating the formation of flame figures (2).

References

1. J Wouters et al., “Mass spectrometry of flame figures”, Acta Derm Venereol, 95, 734 (2015). PMID: 25613159.
2. LM Leiferman, MS Peters, “Eosinophils in Cutaneous Diseases”, Fitzpatrick’s Dermatology in General Medicine, 8th edition. McGraw-Hill Education: 2012.

Submitted by Muhammad Ahsan, Sahiwal Medical College, Sahiwal, Pakistan.