penicillin allergy

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penicillin allergy

A hypersensitivity reaction to penicillin, present in about 0.5% to 8% of the population. Although different types of hypersensitivity reactions may occur, the most common and potentially dangerous are the type I (immediate) reactions mediated by immunoglobulin E. If a patient reports a history of signs of local anaphylaxis (such as urticaria) or systemic anaphylaxis (such as bronchoconstriction, vasodilation) after taking penicillin, no penicillin or other beta-lactam antibiotics (such as cephalosporins) should be given to that patient ever again. In those very rare situations in which an infection is susceptible to no other antibiotic and the infection is serious enough to risk the danger of anaphylaxis, the patient may be desensitized with gradually increasing doses of penicillin.
See also: allergy


any of a large group of natural or semisynthetic antibacterial antibiotics derived directly or indirectly from strains of fungi of the genus Penicillium and other soil-inhabiting fungi grown on special culture media. Penicillins exert a bactericidal as well as a bacteriostatic effect on susceptible bacteria by interfering with the final stages of the synthesis of peptidoglycan, a substance in the bacterial cell wall. Despite their relatively low toxicity for the host, they are active against many bacteria, especially gram-positive pathogens (streptococci, staphylococci); clostridia; certain gram-negative forms; certain spirochetes (Treponema pallidum and T. pertenue); and certain fungi. Certain strains of some target species, for example staphylococci, secrete the enzyme penicillinase, which inactivates penicillin and confers resistance to the antibiotic. Some of the newer penicillins, for example methicillin, are more effective against penicillinase-producing organisms. An additional class of extended-spectrum penicillins has been approved for use; it includes piperacillin and mezlocillin.
There are four groups of penicillins, the natural penicillins, penicillin G and penicillin V, with a narrow spectrum of activity, mainly against gram-positive bacteria; the aminopenicillins (amoxicillin, ampicillin and hetacillin) are semisynthetic derivatives and have a broad spectrum of activity against gram-positive and many gram-negative organisms, but are susceptible to penicillinase-producing Staphylococcus spp.; penicillinase-resistant penicillins, which include cloxacillin, methicillin, nafcillin and oxacillin; and the extended-spectrum penicillins (azlocillin, carbenicillin, mezlocillin, piperacillin and ticarcillin), which are effective against gram-positive and gram-negative organisms, including Pseudomonas aeruginosa.
Allergic reaction to penicillin occurs in some animals. The reaction may be slight—a stinging or burning sensation at the site of injection—or it can be more serious—severe dermatitis or even anaphylactic shock, which may be fatal.

penicillin allergy
degradation products of the penicillins act as haptens, binding to proteins and stimulating an immune response.
penicillin G
benzylpenicillin; the most widely used penicillin; used principally in the treatment of infections due to gram-positive bacteria. Procaine penicillin G is a parenteral preparation that gives extended action for up to 24 hours and benzathine penicillin G is a very slow-release, parenteral preparation that maintains blood levels for several days.
penicillin-induced hemolytic anemia
rare problem in horses which develop IgG anti-penicillin antibodies.
phenoxymethyl penicillin
a biosynthetically or semisynthetically produced antibiotic, similar to penicillin G, for oral administration; not affected by gastric acid and is suitable for oral administration. Its antibacterial spectrum is the same as for penicillin G. Called also penicillin V.
penicillin V
see phenoxymethyl penicillin (above).
References in periodicals archive ?
Of these 100 children, 100% had negative results for penicillin allergy.
Taking the time to confirm or rule out a penicillin allergy can cut down on the use of second-line antibiotics.
Nevertheless, the diagnostic value of sIgE in diagnostics of penicillin allergy is limited due to low sensitivity (40-70%), which also diminishes over time (5).
Even though penicillin allergy was noted in her medical files by Dr Kevin Owens, he was so busy that he forgot, and prescribed the pensioner an antibiotic containing penicillin, Cannock coroner's court heard yesterday.
We noticed a seemingly high prevalence of penicillin allergy in patients who had been diagnosed with peritonsillar abscess (PTA) at our institution.
At the scene an attendant scans the patient's medic alert bracelet that indicates a penicillin allergy.
A total of 192 (98%) of 195 laboratories requested information on patient sex, and 194 (99%) requested information on patient age on requisition forms; fewer collected information on pregnancy status (33%) or penicillin allergy (22%).
Because of a penicillin allergy, 100 mg of doxycycline was given intravenously to the patient every 12 hours for 2 weeks.
We say that not only did she lie when asserting that she had never used drugs but that your Lordship can be confident that she also lied when claiming that her emergency removal from hotel to hospital was the result of a penicillin allergy.
Klepser stresses, however, that they should not be used as a first line of treatment unless in situations of penicillin allergy, high likelihood of penicillin resistance, or deteriorating patient condition.
A single injection of a long-lasting antibiotic can do the job, but such injections are not given often today because they may be quite painful and increase the incidence of penicillin allergy.