Cutaneous adverse drug reactions to allopurinol: 10 year observational survey of the dermatology department--Cagliari University (Italy)

Characteristics of DRESS Syndrome in the Elderly: A Comparative Study of 55 Patients

Background: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare drug reaction characterized by a skin rash, eosinophilia, and organ involvement. Objective: Our purpose is to focus on the clinical and epidemiological characteristics of DRESS in the elderly and to identify the incriminated drugs. Methods: This is a retrospective study including patients, hospitalized for DRESS with a RegiSCAR ≥4. The population was divided into 2 groups according to age: 65 years or older (G1) and <65 years (G2). The statistical study was performed using the comparative and multivariate analysis. Results: We included 55 patients (30.9% G1 and 69.1% G2). Skin manifestations were comparable in both groups. Lymphadenopathy was less common in G1 with a statistically significant difference (P = 0.012). Renal impairment was more frequent in the elderly with a statistically significant result (P = 0.005). DRESS in the elderly group was significantly associated with the occurrence of sepsis (P = 0.008). Allopurinol was the most common culprit associated with DRESS in G1 (P = 0.001). Relapses and recurrences were comparable in both groups (P = 0.71). Conclusions: DRESS in the elderly is associated with a high risk of complications, mainly kidney involvement and sepsis. Allopurinol is the most incriminated drug.

Unusual drug reaction with features of colchicine toxicity in a patient on colchicine and allopurinol

A 58-year-old woman was admitted for heart failure and concern for cardiogenic shock. The patient had been recently placed on colchicine and allopurinol, 4 months and 3 weeks, respectively, prior to admission. Upon admission, she had a cutaneous eruption that had started abruptly several days after allopurinol initiation. It included multiple erythematous papules with scant scale on the forearms and numerous erythematous papules on the legs. Because of the varied morphologic presentation, biopsies from both the thigh and forearm were performed for a suspected drug reaction. The specimen from the thigh showed a superficial-dermal, band-like lymphocytic infiltrate with dyskeratosis and numerous intraepidermal mitotic figures predominantly in metaphase. In addition, there were neutrophils with leukocytoclasia. The specimen from the forearm showed superficial perivascular lymphocytic inflammation and intraepidermal dyskeratosis with mitotic figures similar to the thigh biopsy specimen but without a dermal neutrophilic infiltrate. An unusual drug eruption with features of colchicine toxicity was favored. Colchicine toxicity is not a commonly encountered clinical scenario and cutaneous findings have only rarely been described. Herein we report an exceedingly rare case of an unusual drug reaction with "colchicine figures" (i.e., ring-shaped mitotic figures arrested in metaphase) consistent with colchicine toxicity.

Low-Dose Azathioprine in Combination with Allopurinol: The Past, Present and Future of This Useful Duo

The inflammatory bowel diseases (IBD) are complex immune-mediated inflammatory diseases that are associated with significant morbidity around the world. As our understanding of IBD, and other immune-mediated inflammatory diseases, advances the number of therapeutic targets has increased which has rapidly driven the development and introduction of new therapies. While these new therapies have shown promise they come with the significant drawback of high costs. For many IBD patients around the world the cost of newer therapies is prohibitive which means treating clinicians often need to turn to optimising simpler, older, and inexpensive medications. The concept of optimising well established cheaper medications is not unique to the management of IBD as health systems all over the world look to reduce costs while simultaneously improving patient outcomes. Despite thiopurines being used in the management IBD for over 60 years, many clinicians are still hesitant to use them due to perceptions around limited efficacy and poor tolerance. One method identified to potentially increase utilisation of thiopurines involves the coadministration of allopurinol. In this review we will explore the history, pharmacology, recent studies and give recommendations for the utilisation of the usual duo of azathioprine combined with allopurinol.

Atypical pityriasis rosea in a young Colombian woman. Case report

Introduction: Pityriasis rosea is an acute and self-limited exanthemfirst described by Gilbert in 1860. Its treatment is symptomatic, and although there is no conclusive evidence, it has been associated with the reactivation of the human herpesviruses 6 and 7 (HHV-6 and HHV-7). Case presentation: A 28-year-old woman, from Bogotá, Colombia, ahealth worker, attended the emergency room due to the onset ofsymptoms that began 20 days earlier with the appearance of punctiformlesions in the left arm that later spread to the thorax, abdomen, opposite arm, and thighs. The patient reported a history of bipolar II disorder and retinal detachment. After ruling out several infectious diseases, and due to the evolution of the symptoms, pityriasis rosea was suspected. Therefore, treatment was started with deflazacort 30mg for 21 days, obtaining a favorable outcome and improvement of symptoms after 2 months. At the time of writing this case report, the patient had not consulted for recurrence. Conclusion: Primary care physicians should have sufficient training indermatology to recognize and treat dermatological diseases since manyof them are diagnosed based on clinical findings. This is an atypicalcase, in which the patient did not present with some of the pathognomonic signs associated with pityriasis rosea.

HLA-B*58:01 screening to prevent allopurinol-induced severe cutaneous adverse reactions in Chinese patients with chronic kidney disease

Human leukocyte antigen (HLA)-B*58:01 allele is a significant risk factor for allopurinol-induced severe cutaneous adverse reactions (SCARs) which is potentially fatal. In some studies, chronic kidney disease (CKD) was also implicated to compound the risk of SCARs. We aim to investigate if pre-treatment HLA-B*58:01 screening can prevent allopurinol-induced SCARs in Chinese patients with CKD and its cost-effectiveness. We prospectively recruited Chinese CKD patients who required allopurinol during 2011-2015 and performed pre-treatment HLA testing (HLA screening group). Patients tested positive for HLA-B*58:01 were refrained from allopurinol while those tested negative were prescribed allopurinol. The incidence of SCARs in the HLA screening group was compared with the historical control in previous 5 years and the cost-effectiveness of HLA testing was analyzed. In the historical control (2006-2010), 3605 patients on allopurinol were screened, 22 out of 1027 (2.14%) CKD Chinese patients newly started on allopurinol developed SCARs, including 6 SJS/TEN. In the HLA screening group, 28 out of 192 patients (14.6%) tested HLA-B*58:01 positive were advised to avoid allopurinol; 156 out of 164 HLA-B*58:01-negative patients received allopurinol and none developed SCARs. The incidence rate of SCARs was significantly lower in the HLA screening group compared with controls (0% vs 2.14% respectively, p = 0.037*). The targeted HLA screening approach was associated with lower healthcare costs compared with no HLA screening (US$ 92,430 vs US$ 281,226). Pre-treatment HLA-B*58:01 screening is cost-effective to target on patients with CKD in Chinese to prevent allopurinol-induced SCARs.

Responsiveness to i.v. immunoglobulin therapy in patients with toxic epidermal necrolysis: A novel pharmaco-immunogenetic concept

Toxic epidermal necrolysis (TEN) represents a rare drug-induced autoimmune reaction with delayed-type hypersensitivity that initiates the process of developing massive keratinocyte apoptosis, dominantly in the dermoepidermal junction. Although the etiopathophysiology has not yet been fully elucidated, the binding of Fas ligand (FasL, CD95L) to the Fas receptor (CD95) was shown to play a key role in the induction of apoptosis in this syndrome. The knowledge of the role of immunoglobulin G (IgG) in inhibition of Fas-mediated apoptosis contributed to the introduction of i.v. Ig (IVIg) in the therapy of TEN patients. Despite great enthusiasm for this therapy at the end of the 1990s, subsequent studies in various populations and meta-analyses could not unequivocally confirm the efficacy of the IVIg-based treatment concept. Today, therefore, we are faced with the dilemmas of how to adjust therapy of TEN patients most effectively, which patients could benefit from IVIg therapy and what dose of the preparation should be administrated. The ground-breaking question is: do the host genetic profiles influence the responsiveness and side-effects of IVIg therapy in TEN patients? Based on recent pharmacological, immunological and genetic findings, we suggest that the variability of IVIg therapy outcomes in TEN patients may be related to functional variants in Fas, FasL and Fc-γ receptor genes. This novel concept could lead to improved quality of care for patients with TEN, facilitating personalized therapy to reduce mortality.

Allopurinol-Induced Oral Lichenoid Drug Reaction with Complete Regression after Drug Withdrawal

Background: Lichen planus is a chronic mucocutaneous inflammatory disease. Oral manifestations are common, and may remain exclusive to the oral mucosa without involvement of the skin or other mucosae. A differential diagnosis includes oral lichenoid drug reactions. Allopurinol, which is the first line hypo-uricemic treatment, is often quoted as being a possible offending drug, though oral reactions have rarely been reported. Case presentation: We describe a 59-year-old male gout patient, successfully treated with allopurinol, who developed acute onset of oral lichenoid lesions, involving bilaterally the buccal mucosa, the tongue and the labial mucosa. Histopathology was consistent with a lichen planus or a drug-induced lichenoid reaction. Improvement of the patient's condition after withdrawal of allopurinol confirmed the lichenoid nature of the lesion. Remission was complete after a few weeks. Discussion: Although unusual, allopurinol may induce a lichenoid drug reaction. These reactions may mimic clinically and histopathologically idiopathic lichen planus. Improvement or complete regression of the lesions may be attempted to confirm the diagnosis. According to the latest WHO recommendations, these lesions have a potential for malignant transformation.

Allopurinol-Induced Oral Lichenoid Drug Reaction with Complete Regression after Drug Withdrawal

Background: Lichen planus is a chronic mucocutaneous inflammatory disease. Oral manifestations are common, and may remain exclusive to the oral mucosa without involvement of the skin or other mucosae. A differential diagnosis includes oral lichenoid drug reactions. Allopurinol, which is the first line hypo-uricemic treatment, is often quoted as being a possible offending drug, though oral reactions have rarely been reported. Case presentation: We describe a 59-year-old male gout patient, successfully treated with allopurinol, who developed acute onset of oral lichenoid lesions, involving bilaterally the buccal mucosa, the tongue and the labial mucosa. Histopathology was consistent with a lichen planus or a drug-induced lichenoid reaction. Improvement of the patient’s condition after withdrawal of allopurinol confirmed the lichenoid nature of the lesion. Remission was complete after a few weeks. Discussion: Although unusual, allopurinol may induce a lichenoid drug reaction. These reactions may mimic clinically and histopathologically idiopathic lichen planus. Improvement or complete regression of the lesions may be attempted to confirm the diagnosis. According to the latest WHO recommendations, these lesions have a potential for malignant transformation.

Risk factors for cutaneous reactions to allopurinol in Kinh Vietnamese: results from a case-control study

OBJECTIVE

The aim of this study was to investigate risk factors for cutaneous adverse reactions (CARs) in Kinh Vietnamese.

METHODS

All patients were prospectively recruited in Ho Chi Minh City. Presence of the HLA-B*58:01 allele was determined by real-time PCR-sequence-specific amplification by using the PG5801 Detection Kit (Pharmigene, Taipei). Patients with severe (SCARs) and mild (MCARs) CARs and controls were compared for differences in features prospectively collected, and odds ratios (ORs) with 95% confidence intervals (CIs) were estimated.

RESULTS

On comparing 32 patients with SCARs and 395 tolerant controls, we identified eight strong risk factors: increased age (OR 15.1 [95% CI 5.8-40.1], P < 0.0001), female sex (OR 333 [40-43,453], P < 0.0001), allopurinol for asymptomatic hyperuricemia (OR 955 [120-125,847], P < 0.0001), allopurinol starting dose > 150 mg (OR 316 [101-122], P < 0.0001), diuretics intake (OR 304 [35-40,018], P < 0.0001), eGFR < 60 ml/min/1.73 m² (OR 100 [32-353], P < 0.0001), history of allopurinol-induced skin reaction (OR 78 [6-10,808], P = 0.004), and HLA-B*58:01 carriage (OR 147 [45-746], P < 0.0001). HLA-B*58:01 allele frequency in controls was 7.3%. For MCARs (n = 74), risk factors were eGFR < 60 ml/min/1.73 m² (OR 4.9 [1.61-14.6], P = 0.006), history of allopurinol-induced skin reaction (OR 27 [2-3777], P = 0.01), and asymptomatic hyperuricemia (OR 27 [2-3777], P = 0.01).

CONCLUSION

This study confirmed 8 risk factors, including HLA-B*58:01, for SCARs and identified 3 risk factors for MCARs in Kinh Vietnamese. HLA-B*58:01 genotyping could guide the indication for allopurinol in Kinh Vietnamese patients with gout.

HLA-B*58: 01 association in allopurinol-induced severe cutaneous adverse reactions: the implication of ethnicity and clinical phenotypes in multiethnic Malaysia

OBJECTIVE

The association between human leukocyte antigen (HLA)-B*58:01 and risk of allopurinol-induced severe cutaneous adverse reactions (AIS) was observed across different populations. We explore the association between HLA-B*58:01 and AIS risk in multiethnic Malaysian population. The HLA-B*58:01 risk for different AIS clinical phenotypes and ethnicity was determined.

METHODS

We performed a case-control association study by genotyping the HLA-B alleles of 55 patients with AIS [11 toxic epidermal necrolysis (TEN), 21 Steven Johnson syndrome (SJS) 22 drug reaction wit eosinophilia and systemic symptoms (DRESS) and one acute generalized exanthematous pustulosis (AGEP)] and 42 allopurinol-tolerant controls (ATC).

RESULTS

HLA-B*58:01 was positive in 89.1 and 14.3% of the AIS and ATC study groups [odds ratio (OR) = 49.0, 95% confidence interval (CI) = 14.6-164.4, P < 0.0001)], respectively. Our data showed that 93.8% of the AIS-SJS/TEN patients and 86.4% of the AIS-DRESS patients were HLA-B*58:01 positive (AIS-SJS/TEN, OR = 90, 95% CI = 16.9-470.1, P < 0.0001 and AIS-DRESS OR = 38, 95% CI = 8.5-169.2, P < 0.0001). Stratification by ethnicity and clinical phenotypes revealed a significant increased risk between HLA-B*58:01 and Chinese-AIS patients (OR = 137.5, 95% CI = 11.3-1680.2, P < 0.0001), in particular Chinese patients with AIS-SJS/TEN phenotype (100% HLA-B*58:01 positive). HLA-B*58:01 was positive in 90.9% Chinese AIS-DRESS (P < 0.0001). Highly significant associations of HLA-B*58:01 were observed in Malay AIS-SJS/TEN (OR = 78, 95% CI = 9.8-619.9, P < 0.0001) and Malay AIS-DRESS (OR = 54, 95% CI = 6.6-442.9, P < 0.0001). Although the number of Indian-AIS patients was relatively small (n = 2), both were HLA-B*58:01 positive.

CONCLUSION

Our data suggest strong associations between HLA-B*58:01 and AIS in Malaysian population with Chinese and Malays ethnicity. The strong association was also observed in three different clinical phenotypes of AIS, mainly the AIS-SJS/TEN.

Severe Cutaneous Adverse Drug Reactions Associated with Allopurinol: An Analysis of Spontaneous Reporting System in Southern Italy

Background

Allopurinol can induce severe cutaneous adverse reactions (SCARs), including Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome, Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).

Aims and Methods

We analyzed the Individual Case Safety Reports (ICSRs) sent from January 2001 until April 2019 to the Campania regional Center of Pharmacovigilance (Southern Italy) that reported allopurinol as suspected, with a focus on those reporting at least one serious cutaneous adverse drug reaction (ADR). This study was aimed to describe the main characteristics of all ADRs associated with allopurinol, analyze the proportion of serious cutaneous ADRs of total ICSRs related to allopurinol and to compare the main features (age, sex, seriousness and outcome) of ICSRs that reported serious cutaneous ADRs with those that did not.

Results

The Campania regional Center of Pharmacovigilance received 108 ICSRs that reported allopurinol as suspected. ADRs occurred more frequently in the elderly (median age: 71 years) and female patients (53.7%). Fifty-seven percent of all ADRs were classified as serious and 58% had a favorable outcome. Fifty-six ICSRs reported at least one serious cutaneous ADR; among these ICSRs, 37 cases of SCARs were found [DRESS syndrome (n = 3; 5.4%), SJS (n = 8; 14.3%) and TEN (n = 26; 46.4%)]. Serious cutaneous ADRs commonly occurred in the elderly (median age: 73 years) and female patients (62.5%). They frequently required hospitalization (75%) and had an unfavorable outcome (46%). No statistically significant differences were found between ICSRs that reported serious cutaneous ADRs and ICSRs that did not report serious cutaneous ADRs except for the seriousness degree “Hospitalization or its prolongation” and the outcome degrees “Unfavorable” and “Favorable”.

Conclusion

This study found that 52% (56/108) of all ICSRs having allopurinol as a suspected drug were serious cutaneous ADRs. Serious cutaneous ADRs associated with allopurinol frequently required hospitalization or prolonged hospitalization, and almost half had an unfavorable outcome.

Association of human leukocyte antigen variants and allopurinol-induced Stevens-Johnson syndrome and toxic epidermal necrolysis: A meta-analysis

PURPOSE

The association between human leukocyte antigen (HLA) variants and allopurinol-induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) was evaluated through a pooled analysis of published studies.

METHODS

A comprehensive search was performed in multiple databases, including PubMed, MEDLINE, ISI Web of Knowledge, EMBASE, Cochrane Register of Controlled Trials, and Science Direct. Studies investigating the association between HLA alleles with allopurinol-induced SJS or TEN were retrieved, and the data were independently extracted. The overall odds ratios (ORs) with corresponding 95% confidence intervals were calculated to determine the association between the presence of HLA variant in at least one allele and allopurinol-induced SJS or TEN. To test the robustness of the meta-analysis results, a sensitivity analysis was performed by removing each study one at a time and calculating the pooled ORs of the remaining studies. The fixed-effects and random-effects models were used to pool the collected data.

RESULTS

A total of 4 studies with 81 allopurinol-induced SJS or TEN cases and matched controls (allopurinol-tolerant patients) or population controls (general population) were identified. SJS and TEN were found to be significantly associated with HLA-A*33:03 and HLA-C*03:02 alleles in both groups of studies with matched controls and population controls. All of the pooled ORs were not significantly affected by the remaining studies and different modeling methods, indicating robust results.

CONCLUSION

A strong association was found between HLA-A*33:03 and HLA-C*03:02 alleles and allopurinol-induced SJS or TEN, especially in an Asian population.

Granulomatous rhinitis secondary to feline leishmaniosis: report of an unusual presentation and therapeutic complications

Case summary

A 12-year-old male neutered domestic shorthair cat underwent rhinoscopy due to inspiratory dyspnoea and stertor. Rhinoscopy showed signs of chronic rhinitis and a multinodular nasopharyngeal mucosa. A marked infiltrate of macrophages that contained intracellular parasitic forms morphologically compatible with Leishmania amastigotes were observed on histopathological examination of nasal and nasopharyngeal biopsies. PCR from nasal tissue was positive for Leishmania infantum DNA, confirming the diagnosis of granulomatous rhinitis secondary to this parasite. Two eyelid nodules were identified 2 weeks later. Fine-needle aspiration revealed Leishmania amastigotes within macrophages and in the background. Allopurinol therapy was started, but 5 days later the cat developed dermatological signs compatible with a cutaneous adverse drug reaction. The drug was discontinued and meglumine antimoniate prescribed. Twenty-five days later, the cat presented with acute kidney injury and meglumine antimoniate was discontinued. Despite clinical improvement after fluid therapy, mild azotaemia persisted. The cat was subsequently treated with nucleotides and active hexose correlated compounds (N-AHCC). Four months later upper respiratory signs were exacerbated. A relapse of granulomatous rhinitis was suspected and miltefosine therapy started. Chronic kidney disease (CKD) worsened during miltefosine treatment, having improved under fluid therapy. Since then, the cat has been treated with N-AHCC and renal diet and at the time of writing shows stable CKD with no recurrence of respiratory signs.

Relevance and novel information

This case describes Leishmania infantum as a cause of granulomatous rhinitis in a cat without cutaneous lesions, reporting the alternative use of N-AHCC and miltefosine when allopurinol seemed to have induced a cutaneous rash and there was acute kidney injury (AKI) after meglumine antimoniate therapy.

Systemic Immunomodulating Therapies for Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Systematic Review and Meta-analysis

Importance

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) are rare but severe adverse reactions with high mortality. There is no evidence-based treatment, but various systemic immunomodulating therapies are used.

Objectives

To provide an overview on possible immunomodulating treatments for SJS/TEN and estimate their effects on mortality compared with supportive care.

Data Sources

A literature search was performed in December 2012 for articles published in MEDLINE, MEDLINE Daily, MEDLINE Inprocess, Web of Science, EMBASE, Scopus, and the Cochrane Library (Central) from January 1990 through December 2012, and updated in December 2015, in the English, French, Spanish, and German languages looking for treatment proposals for SJS/TEN. Other sources were screened manually.

Study Selection

Initially, 157 randomized and nonrandomized studies on therapies (systemic immunomodulating therapies or supportive care) for SJS/TEN were selected.

Data Extraction and Synthesis

Relevant data were extracted from articles. Authors were contacted for further information. Finally, 96 studies with sufficient information regarding eligibility and adequate quality scores were considered in the data synthesis. All steps were performed independently by 2 investigators. Meta-analyses on aggregated study data (random-effects model) and individual patient data (IPD) (logistic regression adjusted for confounders) were performed to assess therapeutic efficacy. In the analysis of IPD, 2 regression models, stratified and unstratified by study, were fitted.

Main Outcomes and Measures

Therapy effects on mortality were expressed in terms of odds ratios (ORs) with 95% CIs.

Results

Overall, 96 studies (3248 patients) were included. Applied therapies were supportive care or systemic immunomodulating therapies, including glucocorticosteroids, intravenous immunoglobulins, cyclosporine, plasmapheresis, thalidomide, cyclophosphamide, hemoperfusion, tumor necrosis factor inhibitors, and granulocyte colony-stimulating factors. Glucocorticosteroids were associated with a survival benefit for patients in all 3 analyses but were statistically significant in only one (aggregated data: OR, 0.5; 95%% CI, 0.3-1.01; IPD, unstratified: OR, 0.7; 95% CI, 0.5-0.97; IPD, stratified: OR, 0.8; 95% CI, 0.4-1.3). Despite the low patient size, cyclosporine was associated with a promising significant result in the only feasible analysis of IPD (unstratified model) (OR, 0.1; 95% CI, 0.0-0.4). No beneficial findings were observed for other therapies, including intravenous immunoglobulins.

Conclusions and Relevance

Although all analyses, including the unstratified model, had limitations, glucocorticosteroids and cyclosporine were the most promising systemic immunomodulating therapies for SJS/TEN. Further evaluation in prospective studies is required. However, this work provides a comprehensive overview on proposed systemic immunomodulating treatments for SJS/TEN, which is of great relevance for treating physicians.

Genotyping HLA-B*5801 for Allopurinol-Induced Severe Cutaneous Adverse Reactions: An Accurate and Prompt Method

OBJECTIVES

A new method of HLA-B*5801 genotyping was compared with sequence-based typing (SBT) to find an accurate and prompt method in genotyping HLA-B*5801.

METHODS

Two groups of patients from allopurinol-induced cutaneous adverse reactions (SCARs) and allopurinol-tolerant were both genotyped with PG5801 kit and SBT method. The genotyping results of HLA-B*5801 were compared between the two groups.

RESULTS

The PG5801 detection kit results were 100% (79/79) in agreement with the SBT genotyping results for identifying the HLA-B*5801 (+) patients. No false-positive or false-negative errors were found. The sensitivity, specificity, rate of adherence, positive predictive value (PPV) and negative predictive value (NPV) were 100%.

CONCLUSION

The potential fast screening method is an ideal tool to rule out the high-risk allopurinol-induced SCARs patients.

Lichen planus and other lichenoid dermatoses: Kids are not just little people

Lichenoid dermatoses, a group of inflammatory skin conditions with characteristic clinical and histopathologic findings, range from common to rare. Classic lichen planus typically presents as pruritic, polygonal, violaceous flat-topped papules and plaques; many variants in morphology and location also exist. Other lichenoid dermatoses share similar clinical presentations and histopathologic findings. These include lichenoid drug eruption, lichen planus-like keratosis, lichen striatus, lichen nitidus, and keratosis lichenoides chronica. Epidemiologic characteristics vary among each lichenoid disorder. While classic lichen planus is considered a disease of adults, other lichenoid dermatoses may be more common in younger populations. The literature contains an array of reports on the variations in presentation and successful management of lichen planus and lichenoid dermatoses among diverse populations. Familiarity with the characteristics of each lichenoid dermatosis, rare or common within each patient population, is key to accomplishing timely recognition and effective management.

Genetic markers associated with cutaneous adverse drug reactions to allopurinol: a systematic review

Pharmacogenomic markers in the HLA coding genes have been associated with drug hypersensitivity of multiple drugs, including allopurinol. In this systematic review, we summarize the pharmacogenomic evidence available regarding allopurinol-induced cutaneous adverse drug reactions (cADRs). We found that the HLA-B*5801 allele was significantly associated with the risk of severe cADRs in the Han Chinese, Korean, Thai, Japanese and European populations. The association between less severe cADRs and HLA-B*5801 was less consistent. All SNPs identified in genome-wide association studies of common variants were also located in or nearby HLA-B*5801. Future studies should focus on more common but less severe allopurinol-induced cADRs, as well as the potential role of rare variants as predictors of these cADRs.

Life Threatening, Allopurinol-related Dress Syndrome as a Rare Cause of Fever of Unknown Origin

Drug reaction eosinophilia with systemic symptoms (DRESS) syndrome is a potentially life threatening condition secondary to the usage of a wide type of drugs. A 38-year-old woman under allopurinol therapy for hyperuricemia was admitted in our department with fever and a diffuse cutaneous erythematous eruption. A few days after admission she developed rapidly progressive signs of acute liver and kidney failure. Subsequently, her clinical conditions shortly improved. The histologic findings obtained from skin and liver biopsies were consistent with a toxic drug reaction. The patient completely recovered and has been healthy for five years.

Cost-effectiveness analysis of HLA-B*5801 testing in preventing allopurinol-induced SJS/TEN in Thai population

BACKGROUND

Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), caused by allopurinol therapy, are strongly associated with the human leukocyte antigen (HLA), HLA-B*5801. Identification of HLA-B*5801 genotype before prescribing allopurinol offers the possibility of avoiding allopurinol-induced SJS/TEN. As there is a paucity of evidence about economic value of such testing, this study aims to determine the cost-effectiveness of HLA-B*5801 testing compared with usual care (no genetic testing) before allopurinol administration in Thailand.

METHODS AND FINDING

A decision analytical and Markov model was used to estimate life time costs and outcomes represented as quality adjusted life years (QALYs) gained. The model was populated with relevant information of the association between gene and allopurinol-induced SJS/TEN, test characteristics, costs, and epidemiologic data for Thailand from a societal perspective. Input data were obtained from the literature and a retrospective database analysis. The results were expressed as incremental cost per QALY gained. A base-case analysis was performed for patients at age 30. A series of sensitivity analyses including scenario, one-way, and probabilistic sensitivity analyses were constructed to explore the robustness of the findings. Based on a hypothetical cohort of 1,000 patients, the incremental total cost was 923,919 THB (USD 29,804) and incremental QALY was 5.89 with an ICER of 156,937.04 THB (USD 5,062) per QALY gained. The cost of gout management, incidence of SJS/TEN, case fatality rate of SJS/TEN, and cost of genetic testing are considered very influential parameters on the cost-effectiveness value of HLA-B*5801 testing.

CONCLUSIONS

The genetic testing for HLA-B*5801 before allopurinol administration is considered a highly potential cost-effective intervention in Thailand. The findings are sensitive to a number of factors. In addition to cost-effectiveness findings, consideration of other factors including ethical, legal, and social implications is needed for an informed policy decision making.

The prescription of allopurinol in a tertiary care centre: appropriate indications and dose adjustment

Objective

To determine the appropriateness (both indications and adequate dosage regimen via creatinine clearance estimation) of allopurinol by physicians of different specialties in a tertiary care centre.

Patients and methods

In this cross sectional study computerized clinical records of 156 adult patients who were prescribed allopurinol from 12th November to 11th December, 2011 were retrieved from Al Hada Hospital Taif Saudi Arabia. Main outcome variables were approprsiate indications of allopurinol, prescribing physician’s specialty, and dosage of allopurinol. The prescribed dosages were categorized into correct and incorrect dose adjustments based on creatinine clearance estimation. The SPSS version 16 was utilized for data analyses.

Results

The mean (±SD) age was 58.15 (±14.99) years. There were 105 (67.3%) males and 51 (32.7%) females with male to female ratio being 2:1. Allopurinol was frequently prescribed by nephrologists and family physicians in this study. Out of 156 patients, 46 (29.5%) patients received allopurinol with appropriate indications. Eighty-five (54.5%) patients were received allopurinol without dose adjustment based on their creatinine clearance estimation; among them, 21 (13.5%) received allopurinol with appropriate indications.

Conclusion

The inappropriate use of allopurinol (both the indication and prescribed dosage) is still a major problem in a large tertiary care centre. Furthermore, the specialty of physicians is also a contributory factor in this inappropriateness.

Association between HLA-B*58:01 allele and severe cutaneous adverse reactions with allopurinol in Han Chinese in Hong Kong

BACKGROUND

Allopurinol has been reported as a common cause of severe cutaneous adverse reactions (SCARs). Recent studies in various populations suggest that HLA-B*58:01 is a strong genetic marker for allopurinol-induced SCAR, especially in populations with a high frequency of HLA-B*58:01.

OBJECTIVES

To confirm the association link between HLA-B*58:01 and hypersensitivity reactions attributed to allopurinol use in Han Chinese patients in Hong Kong.

METHODS

We performed a case-control study to investigate whether the HLA-B*58:01 allele predisposes to allopurinol-induced SCAR in Han Chinese patients in Hong Kong. The HLA-B*58:01 genotyping was performed in 20 patients with allopurinol-induced SCAR or erythema multiforme major (EMM; n = 1) and in 30 patients tolerant to allopurinol.

RESULTS

All of the 19 patients with allopurinol-induced SCAR examined but not the patient with EMM carried HLA-B*58:01 whereas only four (13%) of the control patients had this allele. The positive rate of the HLA-B*58:01 was significantly higher in the cases than in the allopurinol-tolerant control group [odds ratio (OR) 123·5, 95% confidence interval (CI) 12·8-1195·1; P < 1 × 10(-4) ] and was even higher after removal of the patient with EMM (OR 229·7, 95% CI 11·7-4520·4). The sensitivity and specificity of the HLA-B*58:01 allele for prediction of allopurinol-induced SCAR were 100% and 86·7%, respectively.

CONCLUSIONS

This study confirmed the strong association between the HLA-B*58:01 and allopurinol-induced SCAR in Hong Kong Han Chinese patients. A screening test for the HLA-B*58:01 allele should effectively reduce the risk for allopurinol-induced SCAR in Chinese populations.