Dermoscopy in eczema: A magnified approach to diagnosis and management

INTRODUCTION

Eczema is a common inflammatory skin disease that affects individuals across all age groups. Eczema, derived from the Greek words ek (out) and zema (boil), literally means “to boil out.”^[1] Characterized by a relapsing course with exacerbations of erythema, scaling, pruritus, and vesiculation, eczema presents significant diagnostic and therapeutic challenges.

Eczema arises from a combination of epidermal barrier dysfunction, immune dysregulation, and environmental triggers. Disruption of the stratum corneum, due to intrinsic defects or external insults, leads to increased trans epidermal water loss and heightened permeability to irritants and allergens. This initiates an immune response, predominantly involving T cells, cytokines such as interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha, and local inflammation. Chronicity results from repeated cycles of inflammation, pruritus, and scratching, further impairing barrier integrity and promoting secondary infections.

Eczema is classified into acute, subacute, and chronic stages, reflecting its evolving clinical presentation and histopathological features over time.^[2] Acute phase manifests as intense itching, redness, swelling, and papulovesicular lesions. The subacute stage is marked by persistent swelling and scaling, while the chronic stage is characterized by dry, fissured, thickened, and lichenified skin.

Eczema is typically diagnosed through a thorough clinical examination. Patch testing may prove valuable in suspected cases of contact eczema affecting the face, hands, or feet, or when the dermatitis is atypical or asymmetrical. Biopsy is rarely necessary.

Effective management involves not only symptom control but also accurate diagnosis, disease monitoring, and timely identification of complications. In this regard, dermoscopy – a non-invasive technique traditionally used in dermatology for the evaluation of pigmented skin lesions, particularly melanomas – has been increasingly integrated into clinical practice for managing eczema.

Dermoscopy involves the use of a handheld device equipped with a light source and magnification lens to examine skin lesions. It provides an in-depth view of epidermal and superficial dermal features, which are not visible to the naked eye.^[3,4] In recent years, this technique has been applied to a variety of dermatological conditions, extending its utility beyond the diagnosis of melanoma and non-melanoma skin cancers to include inflammatory skin disorders like eczema.^[5,6]

DERMOSCOPY IN DIAGNOSIS OF ECZEMA

The diagnosis of eczema is primarily clinical, based on characteristic lesions, patient history, and environmental or genetic triggers. In eczema, dermoscopic findings depend on the stage of the disease (acute, subacute, or chronic). Some of the key dermoscopic and histopathological features identified in eczema are given in Table 1 and their co-relation is depicted in Table 2.

The clinical presentation of eczema can overlap with other inflammatory skin conditions, such as psoriasis, or tinea corporis.^[7,8] This overlap can make diagnosis challenging, especially in complex or atypical cases. Dermoscopy helps in overcoming these diagnostic challenges by providing a more detailed view of the skin’s surface features, thus increasing diagnostic precision.^[6,9]

A summary of dermoscopic and histopathological features of eczema, as reported in previous studies, is presented in Table 3. Certain forms of eczematous dermatitis can present with distinct and unique features.

Stasis dermatitis - globular or glomerular vessels are commonly observed due to elevated hydrostatic pressure.^[9] Pityriasis alba is characterized by diffuse, dull white, structureless areas with blurred margins. Less frequently observed features include incomplete perieccrine brown pigmentation, brown dots, and white scales, which may appear patchy or confined to skin furrows. In addition, incomplete perifollicular brown pigmentation may be present in some cases.^[11-13]

Nummular eczema typically reveals yellow serocrusts with characteristic yellow scales known as the “yellow clod sign.” ^[10] Seborrheic dermatitis - common dermoscopic findings include focal dull white structureless areas, patchy white scales, and patchy yellow scales or crusts. Less frequently observed features include patchy brown scales or crusts, protruding follicular plugs, and vascular patterns such as dotted or linear clustered vessels.^[11]

Hand eczema and palmar psoriasis have significant overlapping clinical features. Both conditions commonly exhibit dotted vessels, though palmar psoriasis shows a higher prevalence of regularly distributed vessels, whereas hand eczema tends to have patchy vessel distribution. Scaling patterns also differ, white scales predominate in palmar psoriasis, while hand eczema often presents with both white and yellow scales or predominantly yellow scales. Background erythema in psoriasis is typically light red, whereas eczema shows a yellowish-dull red background. Additional findings in hand eczema include brownish-orange dots and yellow-orange clods.^[8,9] [Figure 5]

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Figure 1:

Dermoscopy of acute eczema: (a) Acute eczema with erythematous plaque with oozing and crusting with surrounding excoriation marks (b) Dermoscopy showing yellow scales and crusts (Yellow Clod Sign) – (red star), dotted vessels, both distributed in patches (blue arrow), pinkish-yellow background.

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Figure 2:

Yellowish crusts (red star), pinkish yellow background, adherent fabric fiber sign (blue arrow) on dermoscopy of acute eczema.

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Figure 3:

Dermoscopy of subacute eczema: (a) Subacute eczema with erythematous, mildly scaly plaques with excoriations (b) Dermoscopy showing red dots in a patchy and irregular distribution (star), white scales (arrow), yellow serocrusts, excoriations.

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Figure 4:

Dermoscopy of chronic eczema: (a) Chronic eczema with lichenified, thickened, and hyperpigmented skin with scaling and excoriations due to repeated scratching or rubbing (b) Dermoscopy showing white and yellow scales (red star), greyish-white background and an irregular pigment network (blue arrow).

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Figure 5:

Dermoscopy of palmoplantar eczema: (a) Palmoplantar eczema with erythema, scaling, hyperkeratosis, fissuring, and vesicles (b) Dermoscopy showing yellowish white scales (blue arrow) in a diffuse distribution with yellowish homogenous areas (star) on a pinkish white background. Faint yellow globules (green arrow) can be appreciated (Yellow clod sign).

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Asteatotic eczema is frequently identified by the presence of white scales that have a double-free edge, creating a “rail-like” appearance.^[9]

Follicular eczema - Multiple, round, whitish areas with blurry margins surrounding a normal hair follicle with perifollicular scales (author’s own observation) in comparison to perifollicular scales and dotted vessels in follicular psoriasis [Figure 6].

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Figure 6:

Dermoscopy of follicular eczema: (a) Follicular eczema with multiple pruritic, skin-colored to erythematous perifollicular papules seen over the extensor surfaces (b) Dermoscopy showing multiple, round, whitish areas with blurry margins surrounding a normal hair follicle with perifollicular scales (arrow)

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Pigmented contact dermatitis - reticular or patchy pseudo-network with varying shades of brown, gray, and violaceous pigmentation. The background may show gray-brown dots and globules, corresponding to pigment incontinence. Ill-defined patchy pigmentation is common, often with scaling and focal erythema. Fine dotted or linear vessels may be present, but vascular structures are generally sparse [Figure 7].

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Figure 7:

Dermoscopy of pigmented contact dermatitis: (a) Pigmented contact dermatitis with ill-defined, patchy, brown to slate-gray hyperpigmented macules over face and neck, with minimal to no erythema or scaling. (b) Dermoscopy showing brownish background with accentuated pseudo-network and brownish dots and globules (red circle) and erythematous areas (red arrow)

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Erythroderma - the dermoscopic features of underlying skin disorders are often preserved, particularly in cases secondary to psoriasis (especially pustular psoriasis), pityriasis rubra pilaris (PRP), eczema, scabies, and dermatophytosis.^[14] Eczema in erythroderma is commonly characterized by dotted or pinpoint vessels in a patchy distribution, along with profuse white-yellow serocrusts (yellow clods) and scaling. These findings correlate with underlying spongiosis, which can be confirmed histopathologically.^[14-16]

Table 4 mentions the differential diagnosis alongwith dermoscopic clues to differentiate from eczema.^{[6, 9, 16-22]}

DERMOSCOPY IN MONITORING DISEASE ACTIVITY AND TREATMENT RESPONSE

Eczema is a dynamic disease that exhibits fluctuating activity over time. Treatment strategies for eczema generally aim to control acute flares, reduce inflammation, and maintain long-term skin health. Monitoring disease activity is crucial for adjusting treatment protocols and ensuring optimal patient outcomes. Traditional methods of monitoring disease activity, including Eczema Area and Severity Index, Severity Scoring of Atopic Dermatitis, Patient-Oriented Eczema Measure, etc., are largely subjective, relying on clinical evaluation, patient-reported symptoms, and overall appearance.^[16] Dermoscopy offers an objective, reproducible means to monitor disease progression and assess the response to therapy.^[23]

1. Evaluation of inflammatory activity: Dermoscopy provides a detailed view of the extent of vascular changes and scale in eczema lesions, both of which correlate with the degree of inflammation. Increased vascularity and scaling may indicate an active flare, while a reduction in these features can suggest a positive response to treatment.^[23]

2. Accuracy in patch testing: Dermoscopy can improve accuracy in the differential diagnosis between weak allergic and irritant patch test reactions.^[24]

3. Early detection of disease resolution: As the lesions improve, dermoscopy can reveal a gradual reduction in erythema, exudation, and scaling. The disappearance of dilated blood vessels, scaling, and exudation is a positive indicator that the disease is resolving.

4. Assessing the efficacy of topical and systemic therapies: Dermoscopy can be used to evaluate the effectiveness of various therapies, such as topical corticosteroids, calcineurin inhibitors, and newer biologic agents. Changes in vascularity, scaling, and crusting may guide decisions regarding dose adjustments or the introduction of alternative treatments.^[23]

5. Chronic eczema management: Chronic eczema patients often experience long-term skin changes, such as lichenification, thickening, and pigmentation alterations. Dermoscopy can help track these changes, providing a clearer picture of how the skin is adapting to chronic inflammation and whether further interventions are needed to prevent disease progression or complications.

DERMOSCOPY IN COMPLICATIONS OF ECZEMA

Eczema patients are at an increased risk of developing secondary complications. One of the most common complications of eczema is bacterial superinfection, particularly with Staphylococcus aureus. Dermoscopic features suggestive of bacterial involvement include the presence of pustules, crusting, and abscess formation. Pustules may appear as small, well-defined, white or yellowish globules, often surrounded by erythema and honey-colored crusts, which is a hallmark sign of a bacterial infection.^[18] Besides, these patients are also prone to develop viral infections such as herpes simplex virus (HSV) or molluscum contagiosum, which can be identified on dermoscopy by the presence of vesicles, erosions, or hemorrhagic crusts. The characteristic dermoscopic appearance of HSV lesions – such as grouped vesicles and a “dappled” pattern of inflammation – can help distinguish viral infections from other eczema-related changes.^[25]

LIMITATIONS OF DERMOSCOPY IN ECZEMA

Despite its advantages, dermoscopy does have limitations in the management of eczema. Some of these include:

1. Interpretation challenges: While dermoscopy can aid in diagnosing and monitoring eczema, the interpretation of findings may vary between clinicians. Expertise and training are required to correctly identify key features and avoid misdiagnosis.^[26]

2. Overlapping features: Many inflammatory skin conditions share similar dermoscopic features with eczema. This overlap can complicate the diagnostic process, particularly when lesions are atypical.

3. Inability to replace histopathology: Dermoscopy is an adjunct tool, not a replacement for histopathology. In cases of atypical eczema or when the diagnosis is uncertain, biopsy and histopathological examination remain the gold standard for definitive diagnosis.

CONCLUSION

Dermoscopy has emerged as a valuable, non-invasive tool in the diagnosis and management of eczema, offering enhanced visualization of vascular, pigmentary, and structural changes that are not appreciable to the naked eye. Its utility extends beyond diagnosis to monitoring disease activity, assessing treatment response, and identifying complications such as secondary infections. By providing objective and reproducible findings, dermoscopy complements clinical evaluation, reducing diagnostic ambiguity and facilitating individualized treatment strategies. However, its interpretation requires expertise, and it remains an adjunct to traditional diagnostic methods rather than a replacement for histopathology. Future research and standardization of dermoscopic criteria may further refine its role in eczema management, improving patient outcomes through early detection and precise therapeutic interventions.