{{Short description, A rash with central clearing
In
dermatology
Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medica ...
, a target lesion or bull's-eye lesion, named for its resemblance to the bull's-eye of a shooting target, is a
rash
A rash is a change of the human skin which affects its color, appearance, or texture.
A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, c ...
with central clearing. It occurs in several diseases, as follows:
* Target lesions are the typical lesions of
erythema multiforme
Erythema multiforme (EM) is a skin condition that appears with red patches evolving into target lesions, typically on both hands.
It is a type of erythema possibly mediated by deposition of immune complexes (mostly IgM-bound complexes) in th ...
, in which a vesicle is surrounded by an often hemorrhagic maculopapule. Erythema multiforme is often self-limited, of acute onset, resolves in three to six weeks, and has a cyclical pattern. Its lesions are multiform (polymorphous) and include
macule
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this s ...
s,
papule
A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...
s,
vesicles
Vesicle may refer to:
; In cellular biology or chemistry
* Vesicle (biology and chemistry), a supramolecular assembly of lipid molecules, like a cell membrane
* Synaptic vesicle
; In human embryology
* Vesicle (embryology), bulge-like features o ...
, and bullae.
* Target lesions are also typical of
Lyme disease
Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the ''Borrelia'' bacterium, which is spread by ticks in the genus ''Ixodes''. The most common sign of infection is an expanding red rash, known as erythema migran ...
. In the context of Lyme disease, the target lesion is synonymous with
erythema migrans
Erythema migrans or erythema chronicum migrans is an expanding rash often seen in the early stage of Lyme disease, and can also (but less commonly) be caused by southern tick-associated rash illness (STARI). Page last reviewed: October 22, 2015 ...
(erythema chronicum migrans), although not everyone who gets Lyme disease will have a target-shaped rash, and some will have no rash at all.
Causes
Such lesions may be
idiopathic
An idiopathic disease is any disease with an unknown cause or mechanism of apparent spontaneous origin. From Greek ἴδιος ''idios'' "one's own" and πάθος ''pathos'' "suffering", ''idiopathy'' means approximately "a disease of its own kin ...
or may follow
infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dis ...
s,
drug therapy
Pharmacotherapy is therapy using pharmaceutical drugs, as distinguished from therapy using surgery (surgical therapy), radiation (radiation therapy), movement (physical therapy), or other modes. Among physicians, sometimes the term ''medical ther ...