Eosinophilic cellulitis is a rare inflammatory skin disorder. Clinically, it often presents as red, swollen, tender plaques that may be mistaken for bacterial cellulitis. Microscopic examination shows a dense infiltrate of eosinophils within the dermis, together with “flame figures,” deposits of eosinophil granule proteins on collagen fibers. Peripheral eosinophilia is common, but systemic involvement is usually absent.
Why Does Eosinophilic Cellulitis Occur?
The exact cause remains unclear. Many studies suggest that Eosinophilic Cellulitis represents a localized hypersensitivity reaction to various triggers such as infections, insect bites, medications, or vaccinations. Activated eosinophils degranulate in the skin, and pro-inflammatory cytokines like interleukin-5 help recruit eosinophils. Some patients experience recurrent episodes, and in rare cases, eosinophilic cellulitis can be associated with systemic eosinophilic disorders such as hypereosinophilic syndrome.
How Does Eosinophilic Cellulitis Present Clinically?
Clinically, eosinophilic cellulitis is diverse. Many patients develop erythematous, edematous plaques resembling cellulitis, but these lesions often feel cool rather than warm. Some may blister (bullous type) or appear hive-like. Lesions often affect limbs and trunk. Patients may experience itching, but systemic symptoms such as fever are often absent. The disease tends to recur, with episodes resolving spontaneously or responding to mild therapy.
Why Is Eosinophilic Cellulitis Often Misdiagnosed?
Because it resembles bacterial cellulitis, many patients are initially treated with antibiotics. When lesions fail to improve or recur, clinicians may reconsider the diagnosis. Differential diagnosis includes insect bites, drug reactions, urticaria, contact dermatitis, and granuloma annulare. Biopsy and clinical suspicion are essential.
Can a Dermatoscope Detect Eosinophilic Cellulitis?
A dermatoscope is a handheld device that provides magnified, polarized or non-polarized light examination of the skin, allowing clinicians to visualize subtle vascular patterns, pigmentation, and surface structures. It is widely used in the evaluation of pigmented lesions, inflammatory dermatoses, and certain infections. Eosinophilic cellulitis, however, primarily affects the dermis with dense eosinophilic infiltrates. The disease manifests as edematous, erythematous plaques which resemble bacterial cellulitis.
What Skin Conditions Is Dermoscopy Mainly Used to Examine?
The dermatoscope is a powerful, non-invasive imaging tool central to modern dermatological practice. Its primary application focuses on dermato-oncology, where it significantly enhances the diagnostic rate of early melanoma and non-melanoma skin cancers like basal cell carcinoma by providing high-magnification visualization of subtle microstructures indicative of malignant change. Furthermore, the dermatoscope is widely used in the evaluation of pigmentary disorders, aiding in the differentiation and depth assessment of benign moles, atypical nevi, and hypopigmented conditions (such as vitiligo). Its third major utility is in trichoscopy, where it serves to establish differential diagnoses for various inflammatory and non-inflammatory alopecias (e.g., alopecia areata, androgenetic alopecia) by observing characteristic changes in the hair shafts and follicles to guide treatment.
Does Eosinophilic Cellulitis Only Affect the Skin?
Eosinophilic cellulitis is primarily a dermatologic condition, meaning its main pathological and clinical manifestations occur in the skin and subcutaneous tissue. However, it is fundamentally a systemic inflammatory disorder, and while major internal organ involvement is rare, patients can frequently exhibit extracutaneous findings and systemic abnormalities reflecting the eosinophilic burden.
The most common systemic finding is peripheral blood eosinophilia, defined as an elevated count of eosinophils in a complete blood count. This finding strongly supports the diagnosis, especially during the active acute phase of the disease. Other occasional systemic symptoms associated with acute flares include mild fever, headache, joint pain, or muscle pain.
While the skin is the primary target, other organs, such as the lymph nodes, may be involved. Lymphadenopathy can sometimes be detected regionally, particularly near active skin lesions. Unlike other severe eosinophilic diseases, eosinophilic cellulitis typically does not cause significant organ dysfunction in the heart, lungs, or nervous system, which helps distinguish it from conditions like Hypereosinophilic Syndrome (HES). Therefore, while the disease is centered on the skin, the diagnostic workup must include systemic evaluation, particularly a check for peripheral eosinophilia.
Can Eosinophilic Cellulitis Be Treated Effectively?
Eosinophilic cellulitis is generally highly responsive to treatment, although the challenge lies in managing its recurrent nature. The primary goal of therapy is to quickly suppress the excessive eosinophilic inflammation and control symptoms.
The first-line treatment for acute, extensive flares of eosinophilic cellulitis is systemic corticosteroids, typically oral prednisone. The response to prednisone is often dramatic, with lesions beginning to subside within days, which also serves as a therapeutic trial to distinguish the condition from bacterial infection. The steroids are usually administered as a moderate to high dose followed by a slow taper to prevent rapid recurrence upon withdrawal.
For recurrent or chronic cases, or when systemic steroids are contraindicated, other treatment modalities are utilized
．Topical Corticosteroids: High-potency topical steroids are effective for localized or mild lesions.
．Second-line Systemic Agents: These include non-steroidal anti-inflammatory drugs for milder flares, and immunomodulatory agents for difficult-to-manage chronic cases
．Antihistamines: Although they do not affect the underlying inflammation, non-sedating antihistamines are frequently used to control the intense pruritus that defines the acute phase of the disease, significantly improving patient comfort.