Cutaneous adverse reactions to clindamycin: results of skin tests and oral exposure

BACKGROUND: Clindamycin is an antibiotic used in anaerobic and severe complicated infections. It is often selected for patients with a history of allergy to other antibiotics. OBJECTIVES: To study the occurrence of clindamycin hypersensitivity and to determine whether skin tests are useful in cases of suspected clindamycin allergy. METHODS: Six patients with an exanthematous rash and a history strongly suggestive of clindamycin hypersensitivity were studied with skin tests and oral exposure. Cases of suspected adverse drug reactions to clindamycin reported to the National Register of Adverse Effects of Drugs (NRAED) in Finland during 1973-2000 were analysed. RESULTS: In the skin tests true-positive patch test reactions were seen in four of six patients, while 22 healthy control patients were negative. One false-positive and one false-negative patch test reaction were seen. During 1973-2000, 29 suspected cases of skin and/or mucosal membranes affected by clindamycin were reported to the NRAED. CONCLUSIONS: Clindamycin hypersensitivity is not common. Delayed-type allergic reactions occur and patch tests are useful in those cases. Oral exposure is the method of choice if possible, as false-negative and false-positive reactions may occur.     

Negative predictive value of drug skin tests in investigating cutaneous adverse drug reactions

Summary Background Drug skin tests are useful in aetiological analyses of cutaneous adverse drug reactions to determine if the drug can be rechallenged, or to avoid a cross‐reaction with a substitute drug. Objectives To evaluate the negative predictive value of drug skin tests. Methods We retrospectively analysed the files of patients referred for drug reactions. We have enrolled those having strictly determined drug reactions with clinical features, delayed onset after drug intake, drug causality assessment, and negative drug skin tests followed by drug administration. Oral provocation tests or substitution tests with a drug of the same class as that suspected of causing the drug reactions were performed. Results From 1957 files analysed, 200 patients were included. After 403 patch tests, 403 prick tests and 304 intradermal tests, which were all negative, 260 oral provocation tests and 143 substitution tests were done; 307 different drugs were rechallenged. There were 42 positive drug re‐administrations in 27 oral provocation tests and 15 substitution tests. The negative predictive value of our drug skin tests was 89·6%. The negative predictive value for beta‐lactams was 87% for oral provocation tests and 96% for substitution tests, and for corticosteroids it was 100% and 74%, respectively. Conclusions  Negative drug skin tests do not eliminate the responsibility of a drug in drug reactions, and must be followed by drug re‐administration under hospital surveillance.     

Value of patch tests in clindamycin-related drug eruptions

Background. Patch tests help to confirm the aetiology of the cutaneous adverse drug reactions involving delayed hypersensitivity mechanisms, but the results vary with the pattern of skin reaction and the culprit drug. Objectives. To analyse the results of patch tests in patients with cutaneous adverse drug reactions imputable to clindamycin and assess their contribution to the diagnosis. Patients and methods. Between 2005 and 2009, we studied patients with delayed cutaneous adverse drug reactions following administration of clindamycin, usually associated with other drugs. After resolution of the cutaneous adverse drug reaction, patch tests were performed with a series of antibiotics, including pure clindamycin 10% in petrolatum. Results. We studied 30 patients (23 females and 7 males) aged 33–86 years (mean 59.97 years) with generalized maculopapular exanthema where clindamycin was among the highly suspected drugs. Two patients had a previous positive involuntary rechallenge. Patch tests with clindamycin were positive in 9 of 30 patients (30%). More than 50 control patients patch tested with clindamycin were negative. Discussion. We considered the positive patch tests results with clindamycin, in the 9 patients with maculopapular exantema, to be specific, versus the negative results observed in the control group. Although the sensitivity is low (30%), they confirmed the responsibility of this antibiotic in cutaneous adverse drug reactions in which, with only chronological criteria, it was not possible to conclude on the culprit drug.     

Occupational airborne contact allergy to tetrazepam in a geriatric nurse

A 52‐year‐old geriatric nurse presented with recurrent eczema localized in uncovered skin areas. Patch testing produced an eczematous skin reaction with type IV sensitization to tetrazepam. A relapse of contact dermatitis was successfully prevented by using occupational skin protection measures and organizational measures. Our case indicates that a sensitization to drugs should be considered when allergic contact dermatitis is suspected in nursing personnel.     

Evaluation of skin test reactions in patients with non-immediate type drug eruptions

Skin test reactions were evaluated in 242 patients who appeared to develop delayed type drug eruptions from the clinical course. The patch testing was positive in 62 (31.5%) of 197 patients tested and the intradermal testing in 105 (89.7%) of 117 patients. The positive ratios of intradermal testing were higher in maculopapular (MP), erythema multiforme (EM), and erythrodermic (ED) types than in eczematous (Ecz) type drug eruptions, while those of patch testing were comparatively high in ED, Ecz type, and anticonvulsant-induced drug eruptions. It is considered that the combination of patch testing and intradermal testing is useful for determination of causative drugs in delayed type drug eruptions.     

Tetrazepam drug sensitivity -- usefulness of the patch test

The muscle relaxant tetrazepam may cause severe cutaneous adverse effects. We report 4 cases of varying intensity: Stevens-Johnson syndrome, erythema-multiforme-like exanthema, maculopapular and maculo-urticarial exanthema. Patch testing with tetrazepam (10% in petrolatum) was strongly positive in the 2 patients with severe skin eruptions and weakly positive in the other 2. Oral rechallenge with tetrazepam was positive in 3 patients (1 not done). Diazepam, with a similar chemical structure to tetrazepam, was negative on patch testing and on oral challenge testing in 2 patients. Although the optimal patch test concentration of tetrazepam has still to be determined, it is a useful diagnostic tool to confirm sensitization, particularly in patients with severe bullous eruptions.     

抗惊厥药所致药物超敏综合征19例临床特征分析

目的：探讨抗惊厥药所致药物超敏综合征（DHS）的临床特征。方法：回顾分析19例抗惊厥药所致DHS患者的临床表现、实验室检查、治疗方法、并发症及预后。结果：抗惊厥药所致DHS潜伏期长,皮损形态多样,以发疹型为主,常伴有紫癜样斑疹、皮肤肿胀及反复脱屑,多有发热、黏膜损害、浅表淋巴结增大及血常规异常。脏器受累以肝脏为主,肾脏次之。糖皮质激素治疗有效。结论：DHS为具有特征性表现的临床综合征,病程较长,早期、足量地应用糖皮质激素有助于预后的改善。     

过敏性皮肤病患者的接触性变应原分析：基于883例斑贴试验

目的 了解过敏性皮肤病患者接触性变应原特点。方法 回顾性分析883例过敏性皮肤病患者斑贴试验结果,并比较不同性别、年龄、疾病诊断的斑贴试验结果阳性率情况。结果 斑贴试验阳性751例(85.05%)。前6位变应原依次为硫酸镍、重铬酸钾、硫柳汞、卡巴混合物、芳香混合物、夸特15。男性患者重铬酸钾(χ²=48.58)和硫柳汞(χ²=4.36)阳性率均高于女性(均P<0.05)。不同年龄组斑贴试验阳性率差异有统计学意义(χ²=22.33,P<0.01),其中18～45岁和46～59岁组硫酸镍阳性率均高于<18岁组(χ²值分别为4.09、12.06,均P<0.01),18～45岁组卡巴混合物阳性率及46～59岁组重铬酸钾阳性率也均高于<18岁组(χ²值分别为7.50、7.47,均P<0.01);18～45岁组硫柳汞阳性率高于>59岁组(χ²=10.28,P<0.01);而18～45岁组夸特15阳性率低于>59岁组...     

Suppression of immediate-type hypersensitivity elicitation in the skin prick test by ultraviolet B irradiation

Reproducibility of skin prick testing (SPT) and its modulation by ultraviolet B (UVB) radiation is of clinical interest. Sensitized atopic volunteers (groups A and B, n=21) were prick tested with common commercial allergen solutions (undiluted, diluted 1:10 and diluted 1:100) before, 24 h after one and 24 h after three suberythematous UVB irradiations. Volunteers in group A (n=8) received local UVB irradiation of prick test areas, whereas volunteers in group B (n=13) received whole body UVB irradiation, with prick test areas covered. In group A, the wheal intensities, expressed as the ratio allergen wheal size to histamine wheal size, were decreased by 28% (1:10 dilution) (P=0.01) and 45% (1:100 dilution) (P=0.02) after one UVB irradiation. Flare intensities were decreased by 48% (1:10 dilution) (P=0.03) after three UVB irradiations. In group B, the wheal and flare responses tended to decrease. Possible mechanisms of this short-term suppressive effect of UVB irradiation on SPT reactions include a direct effect on mast cells. It is concluded that UV irradiation, even a single exposure, prior to skin testing may compromise the validity of SPT testing.