Uncomplicated skin and skin structure infections (uSSSIs) are a common cause of morbidity in the primary care setting, and oral beta-lactam antibacterials such as the cephalosporins are the traditional treatment of choice for such infections in view of their proven clinical efficacy, favorable tolerability and safety.1 However, physicians tend to avoid using beta-lactams in patients with known or suspected penicillin allergy because of the perceived risk of cross-reactivity reactions,2 which range from immediate-type events such as wheezing, hypotension and laryngoedema through to late reactions such as morbilliform rash and serum sickness.3 Consequently, many patients with uSSSIs and suspected penicillin allergies receive alternative antibacterials that may be less effective and/or poorly tolerated.4
Cefdinir (Omnicef) is an extended-spectrum third-generation cephalo-sporin that has proven clinical efficacy and favorable tolerability in the treatment of uSSSIs.5 Coupled with dosing convenience of twice daily administration, it’s therefore considered to be an excellent, first-line empiric treatment for such infections.1 Moreover, cefdinir is considered highly unlikely to induce an allergic reaction in patients with known or suspected allergy to penicillin,3 indicating that it may not need to be arbitrarily withheld in such individuals. To facilitate clinical decision making, this article presents clinical experience with cefdinir in the treatment of uSSSIs among two such patients.
Case 1
A 42-year-old female presented with a draining cystic lesion on the posterior aspect of her neck. The lesion measured 1.5 cm and was erythematous and draining a serosanguinous fluid. A ruptured sebaceous cyst was diagnosed and the lesion was incised and drained in the office setting. Thereafter, we decided to place the patient on oral antibiotic therapy. The patient noted a history of penicillin allergy, although she did not recall the specifics of the allergic reaction. Cefdinir, 300 mg twice daily for 10 days, was prescribed. On follow-up in the office at 10 days, the patient reported no recurrence of previous allergic reactions and the
cystic lesion had total resolution; no further care was required.
Case 2
A 14-year-old male patient presented with an erythematous, crusted eruption on his chin area. Examination yielded a diagnosis of impetigo, and upon questioning the mother there was a suspected allergy to amoxicillin earlier in his childhood. Cefdinir, 300 mg twice daily for 10 days, was prescribed. Upon follow-up, the impetigo lesions had resolved and no allergic sequelae were noted.
Cephalosporins
Following their introduction, allergic cross-reactivity to cephalosporins was reported in patients with previous penicillin allergies. Based on these early reports, the rate of cross-reactivity was assumed to be approximately 10%6 and has led to the viewpoint that physicians should avoid using cephalosporins in patients with known or suspected penicillin allergy unless they have undergone appropriate allergic testing.7 Such cross-reactivity is thought to be explained by similarities in the chemical structure of the side chain of the beta-lactam ring.8 The cephalosporin cephalothin (Ceporacin, Keflin), for example, has a thiopene 2-acetic acid side chain that closely resembles the phenylacetic acid side chain of benzylpenicillin, while cephalexin (Keflex) and cefprozil (Cefzil) have a side chain function similar to that of amoxicillin (See Figure 1). These similarities probably account for the greater likelihood of allergic reactions with these cephalosporins among penicillin-allergic patients.3
However, the side chain of cefdinir is dissimilar to that of penicillin or amoxicillin, which suggests that this cephalosporin is highly unlikely to induce an allergic reaction in patients allergic to either of these agents.3 This viewpoint is supported by the case studies described here; both patients had suspected penicillin allergy and were successfully treated with cefdinir without recurrence of allergic complications. Such findings accord with previous investigations using chemically dissimilar beta-lactams.7,9–11
In a study of patients with amoxicillin allergy, for example, Miranda et al.9 observed cross-reactivity to cefadroxil (Duricef) in some patients but in none of those treated with cefamandole (Mandole), which is probably explained by the fact that the former shares the same side-chain as amoxicillin whereas cefamandole does not. Romano and colleagues7 also reported cross-reactivity (as determined by skin tests), to cephalosporins that have side-chain structures similar to those of penicillins, but less so for those
with dissimilar side chains, while Novalbos et al.10 challenged penicillin-allergic patients with three cephalosporins that do not share the same side chain as penicillin (cephazoline, cefuroxime and ceftriaxone) without any ill effect.
An Effective Treatment
Cefdinir is a highly suitable empiric therapy for uSSSIs (where the causal organism is likely to be susceptible to the drug) and, on the basis of the clinical experience reported here and existing literature, may not need to be arbitrarily withheld in the patient with a history of suspected of known penicillin allergy. This approach will help to avoid the use of alternative antibacterials that may be less effective and/or poorly tolerated in such patients.
Uncomplicated skin and skin structure infections (uSSSIs) are a common cause of morbidity in the primary care setting, and oral beta-lactam antibacterials such as the cephalosporins are the traditional treatment of choice for such infections in view of their proven clinical efficacy, favorable tolerability and safety.1 However, physicians tend to avoid using beta-lactams in patients with known or suspected penicillin allergy because of the perceived risk of cross-reactivity reactions,2 which range from immediate-type events such as wheezing, hypotension and laryngoedema through to late reactions such as morbilliform rash and serum sickness.3 Consequently, many patients with uSSSIs and suspected penicillin allergies receive alternative antibacterials that may be less effective and/or poorly tolerated.4
Cefdinir (Omnicef) is an extended-spectrum third-generation cephalo-sporin that has proven clinical efficacy and favorable tolerability in the treatment of uSSSIs.5 Coupled with dosing convenience of twice daily administration, it’s therefore considered to be an excellent, first-line empiric treatment for such infections.1 Moreover, cefdinir is considered highly unlikely to induce an allergic reaction in patients with known or suspected allergy to penicillin,3 indicating that it may not need to be arbitrarily withheld in such individuals. To facilitate clinical decision making, this article presents clinical experience with cefdinir in the treatment of uSSSIs among two such patients.
Case 1
A 42-year-old female presented with a draining cystic lesion on the posterior aspect of her neck. The lesion measured 1.5 cm and was erythematous and draining a serosanguinous fluid. A ruptured sebaceous cyst was diagnosed and the lesion was incised and drained in the office setting. Thereafter, we decided to place the patient on oral antibiotic therapy. The patient noted a history of penicillin allergy, although she did not recall the specifics of the allergic reaction. Cefdinir, 300 mg twice daily for 10 days, was prescribed. On follow-up in the office at 10 days, the patient reported no recurrence of previous allergic reactions and the
cystic lesion had total resolution; no further care was required.
Case 2
A 14-year-old male patient presented with an erythematous, crusted eruption on his chin area. Examination yielded a diagnosis of impetigo, and upon questioning the mother there was a suspected allergy to amoxicillin earlier in his childhood. Cefdinir, 300 mg twice daily for 10 days, was prescribed. Upon follow-up, the impetigo lesions had resolved and no allergic sequelae were noted.
Cephalosporins
Following their introduction, allergic cross-reactivity to cephalosporins was reported in patients with previous penicillin allergies. Based on these early reports, the rate of cross-reactivity was assumed to be approximately 10%6 and has led to the viewpoint that physicians should avoid using cephalosporins in patients with known or suspected penicillin allergy unless they have undergone appropriate allergic testing.7 Such cross-reactivity is thought to be explained by similarities in the chemical structure of the side chain of the beta-lactam ring.8 The cephalosporin cephalothin (Ceporacin, Keflin), for example, has a thiopene 2-acetic acid side chain that closely resembles the phenylacetic acid side chain of benzylpenicillin, while cephalexin (Keflex) and cefprozil (Cefzil) have a side chain function similar to that of amoxicillin (See Figure 1). These similarities probably account for the greater likelihood of allergic reactions with these cephalosporins among penicillin-allergic patients.3
However, the side chain of cefdinir is dissimilar to that of penicillin or amoxicillin, which suggests that this cephalosporin is highly unlikely to induce an allergic reaction in patients allergic to either of these agents.3 This viewpoint is supported by the case studies described here; both patients had suspected penicillin allergy and were successfully treated with cefdinir without recurrence of allergic complications. Such findings accord with previous investigations using chemically dissimilar beta-lactams.7,9–11
In a study of patients with amoxicillin allergy, for example, Miranda et al.9 observed cross-reactivity to cefadroxil (Duricef) in some patients but in none of those treated with cefamandole (Mandole), which is probably explained by the fact that the former shares the same side-chain as amoxicillin whereas cefamandole does not. Romano and colleagues7 also reported cross-reactivity (as determined by skin tests), to cephalosporins that have side-chain structures similar to those of penicillins, but less so for those
with dissimilar side chains, while Novalbos et al.10 challenged penicillin-allergic patients with three cephalosporins that do not share the same side chain as penicillin (cephazoline, cefuroxime and ceftriaxone) without any ill effect.
An Effective Treatment
Cefdinir is a highly suitable empiric therapy for uSSSIs (where the causal organism is likely to be susceptible to the drug) and, on the basis of the clinical experience reported here and existing literature, may not need to be arbitrarily withheld in the patient with a history of suspected of known penicillin allergy. This approach will help to avoid the use of alternative antibacterials that may be less effective and/or poorly tolerated in such patients.
Uncomplicated skin and skin structure infections (uSSSIs) are a common cause of morbidity in the primary care setting, and oral beta-lactam antibacterials such as the cephalosporins are the traditional treatment of choice for such infections in view of their proven clinical efficacy, favorable tolerability and safety.1 However, physicians tend to avoid using beta-lactams in patients with known or suspected penicillin allergy because of the perceived risk of cross-reactivity reactions,2 which range from immediate-type events such as wheezing, hypotension and laryngoedema through to late reactions such as morbilliform rash and serum sickness.3 Consequently, many patients with uSSSIs and suspected penicillin allergies receive alternative antibacterials that may be less effective and/or poorly tolerated.4
Cefdinir (Omnicef) is an extended-spectrum third-generation cephalo-sporin that has proven clinical efficacy and favorable tolerability in the treatment of uSSSIs.5 Coupled with dosing convenience of twice daily administration, it’s therefore considered to be an excellent, first-line empiric treatment for such infections.1 Moreover, cefdinir is considered highly unlikely to induce an allergic reaction in patients with known or suspected allergy to penicillin,3 indicating that it may not need to be arbitrarily withheld in such individuals. To facilitate clinical decision making, this article presents clinical experience with cefdinir in the treatment of uSSSIs among two such patients.
Case 1
A 42-year-old female presented with a draining cystic lesion on the posterior aspect of her neck. The lesion measured 1.5 cm and was erythematous and draining a serosanguinous fluid. A ruptured sebaceous cyst was diagnosed and the lesion was incised and drained in the office setting. Thereafter, we decided to place the patient on oral antibiotic therapy. The patient noted a history of penicillin allergy, although she did not recall the specifics of the allergic reaction. Cefdinir, 300 mg twice daily for 10 days, was prescribed. On follow-up in the office at 10 days, the patient reported no recurrence of previous allergic reactions and the
cystic lesion had total resolution; no further care was required.
Case 2
A 14-year-old male patient presented with an erythematous, crusted eruption on his chin area. Examination yielded a diagnosis of impetigo, and upon questioning the mother there was a suspected allergy to amoxicillin earlier in his childhood. Cefdinir, 300 mg twice daily for 10 days, was prescribed. Upon follow-up, the impetigo lesions had resolved and no allergic sequelae were noted.
Cephalosporins
Following their introduction, allergic cross-reactivity to cephalosporins was reported in patients with previous penicillin allergies. Based on these early reports, the rate of cross-reactivity was assumed to be approximately 10%6 and has led to the viewpoint that physicians should avoid using cephalosporins in patients with known or suspected penicillin allergy unless they have undergone appropriate allergic testing.7 Such cross-reactivity is thought to be explained by similarities in the chemical structure of the side chain of the beta-lactam ring.8 The cephalosporin cephalothin (Ceporacin, Keflin), for example, has a thiopene 2-acetic acid side chain that closely resembles the phenylacetic acid side chain of benzylpenicillin, while cephalexin (Keflex) and cefprozil (Cefzil) have a side chain function similar to that of amoxicillin (See Figure 1). These similarities probably account for the greater likelihood of allergic reactions with these cephalosporins among penicillin-allergic patients.3
However, the side chain of cefdinir is dissimilar to that of penicillin or amoxicillin, which suggests that this cephalosporin is highly unlikely to induce an allergic reaction in patients allergic to either of these agents.3 This viewpoint is supported by the case studies described here; both patients had suspected penicillin allergy and were successfully treated with cefdinir without recurrence of allergic complications. Such findings accord with previous investigations using chemically dissimilar beta-lactams.7,9–11
In a study of patients with amoxicillin allergy, for example, Miranda et al.9 observed cross-reactivity to cefadroxil (Duricef) in some patients but in none of those treated with cefamandole (Mandole), which is probably explained by the fact that the former shares the same side-chain as amoxicillin whereas cefamandole does not. Romano and colleagues7 also reported cross-reactivity (as determined by skin tests), to cephalosporins that have side-chain structures similar to those of penicillins, but less so for those
with dissimilar side chains, while Novalbos et al.10 challenged penicillin-allergic patients with three cephalosporins that do not share the same side chain as penicillin (cephazoline, cefuroxime and ceftriaxone) without any ill effect.
An Effective Treatment
Cefdinir is a highly suitable empiric therapy for uSSSIs (where the causal organism is likely to be susceptible to the drug) and, on the basis of the clinical experience reported here and existing literature, may not need to be arbitrarily withheld in the patient with a history of suspected of known penicillin allergy. This approach will help to avoid the use of alternative antibacterials that may be less effective and/or poorly tolerated in such patients.
