Erythema L53.91

• Synonyms: Reddening of the skin, erythema
• Circumscribed, variably sized, polyaetiological (exogenously or endogenously induced) solitary, sharply or indistinctly circumscribed, pale to deep red or bluish-livid, normothermic or hyperthermic, or more rarely hypothermic, red, anaemic patch. An erythema differs in color, size, arrangement, and presents as a contrast to the non-reddened, bright surroundings and is also perceptible only by this contrast. In a universal redness, an erythroderma naturally lacks contrast with a normal environment.
• Furthermore, in the evaluation of 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 (various body regions, field skin, groin) 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, hemorrhagic [transition to purpura], blue-red)
  • temperature (hypo-, normo-, hyperthermic)
  • consistency (unchanged, slightly to moderately increased [palpable erythema as transition to papule])
  • 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.
  • Associated with fever and/or other general symptoms (arthralgias, intestinal symptoms, fatigue).
• Furthermore, a distinction must be made between solitary erythema and erythema as a partial symptom of a generalized or exanthematous disease (e.g. drug exanthema or classical infectious diseases). In English, this flaring up of erythema is called a "flare up". In most cases, this distinction can be made by visual diagnosis. It is of great importance for the further examination procedure (exclusively regional examination or whole body examination). Another important aspect to 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 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 "simple constellation" requires an important and diagnostically advanced examination. It is the clinical decision whether a red spot is anaemic or not. For differential diagnostic reasons, it is fundamentally necessary to separate the red anemizable spots, i.e., erythema, from the dermal hemorrhagic diseases (red nonanemizable spots). Underlying the non-anaemizable red spot is a haematoma of the skin, a purpura. The diagnosis "purpura" requires a fundamentally different examination cascade than the diagnosis "erythema". Thus, this extremely simple examination, which can be performed by means of a glass spatula or even more simply by means of finger compression, is absolutely necessary for the assessment of a red spot.