1. A breaking out, especially the appearance of lesions on the skin. 2. A rapidly developing dermatosis of the skin or mucous membranes, especially when appearing as a local manifestation of one of the exanthemata; an e. is characterized, according to the nature of the lesion, as macular, papular, vesicular, pustular, bullous, nodular, erythematous, etc. 3. The passage of a tooth through the alveolar process and perforation of the gums. [L. e-rumpo, pp. -ruptus, to break out]
- accelerated e. a dental e. pattern which is chronologically advanced in comparison with the average pattern of dental e.; e. of the first tooth occurs at an earlier age than the average, and the intervals of time between subsequent dental eruptions are shorter than the average.
- butterfly e. SYN: butterfly (2).
- clinical e. development of the crown of a tooth that can be observed clinically.
- continuous e. the e. of a tooth into the mouth and its continuous movement in a vertical direction.
- creeping e. SYN: cutaneous larva migrans.
- delayed e. a dental e. pattern which is chronologically late in comparison with the average pattern of dental e.; e. of the first tooth occurs at a later age than the average, and the intervals of time between subsequent dental eruptions are longer than the average.
- drug e. any e. caused by the ingestion, injection, or inhalation of a drug, most often the result of allergic sensitization; reactions to drugs applied to the cutaneous surface are not generally designated as drug e., but as contact-type dermatitis. SYN: dermatitis medicamentosa, dermatosis medicamentosa, medicinal e..
- feigned e. SYN: dermatitis artefacta.
- fixed drug e. a type of drug e. that recurs at the same site (or sites) following the administration of a particular drug; the lesions usually consist of intensely erythematous and purplish, sharply demarcated macules, and occasionally of herpetic vesicles; the affected areas undergo gradual involution, but flare and enlarge on readministration of the offending drug and may become hyperpigmented.
- iodine e. an acneform or follicular e. or granulomatous lesion caused by a reaction to systemic iodine or iodide administration.
- Kaposi varicelliform e. a now rare complication of either herpes simplex or vaccinia superimposed on atopic dermatitis, with generalized vesicles and vesicopapules and high fever.
- medicinal e. SYN: drug e..
- passive e. the apparent continued e. of the teeth, actually the result of regression of the gingivae and crestal bone.
- polymorphous light e. a common pruritic papular e. appearing in a few hours and lasting up to several days on skin exposed to shortwave ultraviolet light (UVB); subepidermal edema and deep perivascular lymphocytic infiltration is seen microscopically.
- seabather's e. pruritic rash believed to result from hypersensitivity to the venom of the larval thimble jellyfish (Linuche unguiculata).
- e. sequestrum (se′kwes-trum) spicule of bone overlying the central occlusal fossa of an erupting permanent molar.
- surgical e. the uncovering of an unerupted tooth to permit its further e. into the oral cavity by surgically removing overlying soft tissue, bone, and sometimes teeth.

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erup·tion i-'rəp-shən n
1) an act, process, or instance of erupting <the \eruption of the tooth from the gum> specif the breaking out of an exanthem or enanthem on the skin or mucous membrane (as in measles)
2) something produced by an act or process of erupting: as
a) the condition of the skin or mucous membrane caused by erupting
b) one of the lesions (as a pustule) constituting this condition

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1. the outbreak of a rash. A bullous eruption is an outbreak of blisters.
2. (in dentistry) the emergence of a growing tooth from the gum into the mouth.

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erup·tion (ĕ-rupґshən) [L. eruptio a breaking out] 1. a breaking out, appearing, or becoming visible. 2. any of various skin lesions due to disease; see also exanthem and rash. 3. tooth e.

Medical dictionary. 2011.