In this group of diseases, the terms eczema and dermatitis, are often used interchangeably. This is an inflammatory disorder of the skin caused by endogenous and exogenous factors. In this chapter, we shall deal with endogenous eczema exclusively. Eczema due to exogenous factors will be covered in Chapter 3. Eczema is the commonest skin disorder seen in most outpatient dermatologic clinics as well as the commonest skin disorder seen in Asians. Tropical climates with high heat, humidity, and frequent perspiration often trigger or exacerbate eczema.
Morphologically, eczema may present in different phases which are classified into acute, subacute, and chronic (Figures 2–1, 2–2, 2–3, 2–4, 2–5, 2–6, 2–7, 2–8, 2–9, 2–10). Acute eczema presents with erythema, papules, edema, vesiculation, and occasionally bullae. Subacute eczema presents with mild erythema, edema and occasional vesiculation. Chronic eczema presents as lichenified, scaly, erythematous patches occasionally with fissures, excoriations, and pigmentary changes. Prurigo and generalized exfoliative dermatitis are other less common manifestations of endogenous eczema.
Infected acute eczema is present over the cheeks of this infant. Atopic eczema in infancy and young children often involves convex surfaces such as the cheeks, forehead, or scalp as well as the trunk and extensor surfaces.
This photo illustrates the features of acute dermatitis on the patient’s ring finger. There is erythema, edema, weeping, and a vesiculobullous eruption. Acute dermatitis may develop as part of endogenous eczema or as part of allergic or irritant contact dermatitis. Vesiculation, which is a manifestation of eczema over the palmar hands and volar feet, is referred to as pompholyx.
Acute vesicular eczema—histology
In acute vesicular eczema, the intense intercellular edema produces large intraepidermal spongiotic vesicles. The adjacent epidermis may be unaffected due to the acute process, or it may show compact hyperkeratosis and acanthosis if there is pre-existing chronic eczema. A common feature is the presence of conspicuous spongiosis in the adjacent epidermis.
This patient with atopic dermatitis has slightly scaly, erythematous patches on his anterior abdomen. Superficial excoriations are seen. Subacute eczema has features midway between acute and chronic eczema. Instead of florid erythema and weeping, the erythema of subacute eczema is often less intense than that in acute eczema. Some scaling and crusting is seen as the acute eczema heals and subacute features become more prominent.
This child was diagnosed with atopic eczema since six months of age and presents with worsening of his rash over the last few weeks. There are subacute eczematous rashes ...