An eschar contains necrotic tissue, whereas a scab is composed of dried blood and exudate. A scar-like scab called eschar is a good indicator of infection, but is not ubiquitous. Morbilliform rash, eschar, splenomegaly, and lymphadenopathies are typical signs. The tough leathery tissue remaining after a full-thickness burn has been termed "eschar". The term "eschar" is not interchangeable with "scab". If circulation is compromised, an escharotomy, or surgical incision through the eschar, may be indicated. Biopsies or cultures of a person's tick wound (eschar) are used to diagnose ATBF. The eschar, by virtue of this inelasticity, results in the burn-induced compartment syndrome. During an escharotomy the patient is often sedated despite the insensible eschar. The incisions should be deep enough to release all restrictive effects from the eschar. This is the cause of the characteristic eschar. Unless it is actively searched for, the eschar most likely would be missed. Usually there is only one eschar unless there has been more than one tick bite.