Erythema L53.91

Circumscribed, variably sized, polyetiologic (exogenously or endogenously triggered) solitary, sharply or indistinctly circumscribed, pale to deep red or bluish-livid, normothermic or hyperthermic or, more rarely, hypothermic, red, always anemic spot.

An erythema differs in color, size, arrangement and presents itself as a contrast to the non-reddened, bright surroundings and is also perceptible only by this contrast. In a dark skin, depending on the pigmentation type, an erythema is only faintly visible or not visible at all. This complicates the morphological diagnosis immensely.

In the case of a universal redness of the entire integument, an erythroderma, the contrast to a normal environment is naturally missing.

Furthermore, when evaluating a solitary erythema or multiple erythemas, various clinical aspects must be considered and diagnostically evaluated. These are in particular:

• Size
• number and distribution (solitary, multiple, grouped, disseminated, exanthematous, universal)
• Dynamics (static, acutely transient, acutely persistent, chronically persistent, crescendo reaction with increasing dynamics, wave dynamics with increasing phase, plateau phase and decrescendo phase)
• Arrangement and shape (gyrated, herpetiform, serpiginous, in Blaschko lines, segmental, anular, shooting disk- or cocard-like, polymorphic, reticular, defined by exogenous trigger, random)
• Structural and functional assignment (follicular, sweat glands, sebaceous glands, contact areas, textile-covered, heliotrope, random)
• Topographical assignment (versch. Body regions, field skin, groin skin, face, nose, auricle, capillitium, intertriginous)
• Boundary (sharp-edged, fuzzy, scalloped, jagged, random)
• color (dull red, light red, deep red, blue-red)
• temperature (hypo-, normo-, hypertherm)
• Consistency (as a spot - unchanged from surrounding skin; a "palpable erythema" would mark the transition to a papule with incipient, inflammatory infiltration)
• Symptomatology (mild itching, severe itching, burning itching, pain)
• Association with metabolic diseases, pregnancy, malignant tumors, autoimmune diseases.
• Exogenous triggering: physical (cold, heat, pressure, UV rays), biochemical (exertion, water, irritants), allergic (contact allergens), bacterial or mycotic infections.
• Endogenous triggering: bacterial, viral, mycotic infections, UAW (drug reactions), food allergies.
• Association with fever and/or other general symptoms (arthralgias, intestinal symptoms, lassitude).

A distinction must be made between solitary erythema and erythema as a partial symptom of a generalized or exanthematous disease (e.g., macular drug erythema or classic infectious macular exanthema). In English, this flaring up of an erythema is called a "flare up." This distinction can be made by visual diagnosis in most cases. It is of great importance for the further examination procedure (exclusively regional examination or whole-body examination).

Another important aspect that can be assessed by visual diagnosis is the heliotropy of an erythema, the dynamics of an erythema (acute or persistent) and the assessment of the general condition of macular exanthema.

• Erythema (large spots, homogeneous), solitary: erysipelas; erysipeloid; tinea corporis; acute dermatitis, allergic; dermatitis solaris; actinic dermatitis; dermatomyositis, fixed toxic drug exanthema; erythema dyschromicum perstans; erythema chronicum migrans; acrodermatitis chronica atrophicans; lichen planus atrophicans; nevus flammeus; large parapsoriasis en plaques; ulerythema ophryogenes; rosacea; lupus erythematosus; erythrasma; pellagra; pellagroid; erythema diffusum hepaticum; erythromelalgia; Erythrosis interfollicularis colli; Pityriasis rubra pilaris; Erythema e pudore; Flush phenomena Erythema e calore; Erythroplasia; Erysipelas carcinomatosum;
• erythema (small spots, macular), multiple (exanthematic): pityriasis versicolor; erythema in (infectious) morbilliform, rubeoliform, scarlatiniform exanthema; pityriasis rosea; erythema infectiosum; drug exanthema; erythema multiforme; erythema elevatum diutinum; persistent cholinergic erythema; erythema anulare rheumaticum; erythema anulare centrifugum; erythema gyratum repens; lichenoid actinic keratosis.

A "red spot" is a frequent constellation of symptoms, its recognition highly simple. And yet, this seemingly "simple constellation" requires further diagnostic consideration and examination: It is the important clinical analysis whether a red spot is anemizable (erythema) or not (hemorrhage). This analysis is basically necessary for differential diagnostic reasons, since the red anemizable spots, i.e. erythema, must be separated from the dermal hemorrhagic diseases (red non-anemizable spots e.g. in purpura).

Underlying the non-anemizable red spot is cutaneous hemorrhage. The diagnosis"purpura" requires a fundamentally different examination cascade than the diagnosis "erythema".