Immunopathogenesis of hypersensitivity syndrome reactions to sulfonamides

Cytokines play a role in the immunopathological and molecular mechanisms of sulfonamide-induced hypersensitivity reactions (HSRs). The objective of this study was to analyze the reliability and correlation between the clinical symptoms observed in affected patients (n = 86) because of a sulfonamide-induced HSR and their lymphocyte toxicity assay (LTA) values. Another goal was to determine the cytokine secretion in the patient's sera and their expression in the peripheral blood mononuclear cells (PBMCs) and to explore whether a correlation exists among positive LTA score, cytokine levels, and HSR occurrence. The final goal is to determine whether these measures could be used to predict the likelihood of a patient to experience an HSR during sulfonamide treatment. Such a predictive ability would be valuable to the clinician to know whether the patient would tolerate sulfonamides or whether an alternative antibiotic should be prescribed. The LTA showed a good correlation with the clinical involvement of patients with hypersensitivity syndromes. In addition, the pro-inflammatory cytokines presented significant differences in patients that had rash, fever, and organ involvement than in control patients or any of the other patient groups. Expression of tumor necrosis factor alpha (TNF-alpha) is significantly higher in patients presenting rash, fever, and organ involvement versus all other groups. It is concluded that a positive LTA is a predictor for sulfonamide-induced true HSR. In addition, T-helper cell 1 cytokines [TNF-alpha, interleukins (ILs) 1 and 2] as well as the chemokine regulated upon activation, normal T-cell expressed and secreted (RANTES) control the pathogenesis of sulfonamide-induced HSR and may be used in early diagnosis of the syndrome.

Canadian consensus statement on the use of intravenous immunoglobulin therapy in dermatology

BACKGROUND

As a safe, well-tolerated, and potentially beneficial therapy, intravenous immunoglobulin (IVIG) has been increasingly used by dermatologists to treat immune-mediated skin disease. However, practical and comprehensive guidelines for the use of IVIG have yet to be established.

OBJECTIVE

To develop the first Canadian consensus statement on the use of IVIG therapy in skin disease.

METHODS

A group of Canadian dermatologists convened to discuss current issues in IVIG therapy. The participants reviewed and evaluated the literature and shared clinical experience. Using a modified Delphi process, a consensus statement was developed.

RESULTS

Herein we provide a brief overview of pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid, mucous membrane pemphigoid, epidermolysis bullosa acquisita, Stevens-Johnson syndrome, and toxic epidermal necrolysis. Recommendations for the management of these diseases are detailed, and therapeutic algorithms for the treatment of various autoimmune mucocutaneous blistering diseases are presented. The appropriate use of IVIG therapy is placed in context for each disease.

CONCLUSION

Although preliminary data suggest that IVIG is a safe and effective therapy for many skin disorders, uncontrolled clinical trials, case series, and anecdotal case reports dominate the literature. Collaborative randomized controlled trials are required to firmly establish the role of IVIG in dermatology.

Recognition and Management of Severe Cutaneous Drug Reactions

Cutaneous drug reactions are among the most common types of adverse drug reactions. This article focuses on the recognition and management of severe cutaneous drug eruptions, including the drug-hypersensitivity syndrome, serum sickness-like reaction, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, and toxic epidermal necrolysis. Cutaneous reactions are considered severe when they can result in serious skin damage or involve multiple organs. Some of these reactions can cause significant morbidity or death. Each may be confounded by diagnostic difficulties, confusion in ascertaining causality, and treatment challenges.

IVIG for the treatment of toxic epidermal necrolysis

Intravenous immunoglobulin (IVIG) has been proposed as a treatment for toxic epidermal necrolysis (TEN) and Stevens-Johnson Syndrome (SJS). A number of retrospective and prospective studies have been conducted, with varying levels of evidence for the efficacy of IVIG. Recent publications provide opposing conclusions. A multi-center, comparative, long-term analysis needs to be conducted to determine the role of IVIG in the management of patients with SJS/TEN.

Povidone-Iodine–Induced Burn: Case Report and Review of the Literature

Burns are a rare but potentially serious complication of povidone-iodine use. This rare adverse drug reaction developed in a 38-year-old woman who underwent laparoscopic right ovarian cystectomy and endometrial ablation as a day procedure involving application of the topical antiseptic 10% povidone-iodine solution. Two days later, the patient was admitted to the hospital with burning, pain, itching, marked redness, and blistering extending from her midback to buttocks. A stain on her back also was evident. Partial-thickness chemical burn was diagnosed. Review of the literature yielded 13 other cases of povidone-iodine-induced burn. This underrecognized adverse effect of povidone-iodine application typically occurs when the povidone-iodine has not been allowed to dry or has been trapped under the body of a patient in a pooled dependent position. The burn is usually seen immediately after the procedure or on the next day, and typically heals with minimum scarring within 3-4 weeks with conservative treatment. The commonly postulated mechanism is a chemical burn due to irritation coupled with maceration, friction, and pressure. Given the widespread use of povidone-iodine and the potential for development of infection after a burn, clinicians need to be aware of this possible povidone-iodine-associated adverse drug reaction, and of preventive measures.

Efalizumab, a reversible T-cell modulator for psoriasis

The humanized monoclonal antibody (MAb) efalizumab (Raptiva) was developed to meet a longstanding need for specific, safe, and effective anti-psoriatic treatments. Efalizumab, which is directed at the lymphocyte surface protein LFA-1, prevents multiple interactions between T cells and other cell types. Here, we review the inflammatory pathway that drives the development of psoriasis, and we discuss several mechanisms by which efalizumab suppresses skin inflammation in psoriasis. Efalizumab reversibly increases circulating T-cell counts, as T cells--including pathogenic CD8 memory T cells that are prominent in psoriatic lesions-- are specifically restrained from leaving the bloodstream and entering the skin. Within two weeks of the onset of efalizumab treatment, cell surface and intracellular LFA-1 pools are substantially cleared by lysosomal degradation. Residual surface LFA-1 molecules remain saturated with bound efalizumab for some weeks following cessation of treatment. Efalizumab's pharmacodynamic properties are consistent with its profound and reversible beneficial effects on the histopathology of psoriatic skin.

CLinical experience acquired with the efalizumab (Raptiva® ) (CLEAR) trial in patients with moderate-to-severe plaque psoriasis: results from a phase III international randomized, placebo-controlled trial

BACKGROUND

Efalizumab (anti-CD11a), a humanized monoclonal antibody, blocks multiple T-cell-dependent functions implicated in the pathogenesis of psoriasis, including T-cell activation, migration to the skin, reactivation in psoriatic skin and interactions with keratinocytes.

OBJECTIVES

This multinational, randomized, double-blind, placebo-controlled, parallel-group trial was designed to evaluate the safety and efficacy of subcutaneous efalizumab 1.0 mg kg-1 once weekly for 12 weeks compared with placebo in a population that included high-need patients, defined as those for whom at least two systemic therapies were unsuitable because of lack of efficacy, intolerance or contraindication.

PATIENTS/METHODS

Patients with moderate-to-severe plaque psoriasis [involvement of >or=10% of total body surface area and Psoriasis Area and Severity Index (PASI)>or=12.0 at screening] were randomized in a 2:1 ratio to receive efalizumab or placebo. The primary efficacy endpoint was the proportion of patients achieving >or=75% PASI improvement (PASI-75 response) at week 12 in the intention-to-treat population; secondary endpoints included changes in PASI, static Physician's Global Assessment, Physician's Global Assessment of change from baseline and percentage of body surface area affected. Results We enrolled 793 patients (529 received efalizumab and 264 placebo), including 526 high-need patients (342 received efalizumab and 184 placebo). Week 12 PASI-75 rates were 29.5% for efalizumab compared with 2.7% for placebo among high-need patients (P<0.0001) and 31.4% for efalizumab compared with 4.2% for placebo in the full study population (P<0.0001).

RESULTS

for all secondary efficacy endpoints showed superiority of efalizumab over placebo in both the high-need and the full populations. Efalizumab demonstrated a favourable safety profile, without evidence of systemic toxicity, in both the high-need group and the overall study population.

CONCLUSIONS

The efficacy and safety of efalizumab therapy were comparable between high-need patients and the more general moderate-to-severe psoriasis patient population. In view of its demonstrated efficacy and safety profile, efalizumab represents a valuable option for the treatment of adult patients with moderate-to-severe plaque psoriasis, including high-need patients.

Socioeconomic status influences care of patients with acne in Ontario, Canada

BACKGROUND

Canada's universal health care system is designed to ensure equitable access to medical care based on need rather than socioeconomic status, although a number of studies indicate a preferential access and greater use of specialist services for those patients in higher socioeconomic groups.

OBJECTIVES

The primary objective of this study was to determine whether socioeconomic status influences access to specialist care by a dermatologist for the management of acne in Ontario, Canada. A secondary objective was to determine whether the urban-rural dwelling status of patients affects access to specialty care.

METHODS

We conducted a population-based cohort study using administrative health care databases covering more than 12 million residents of Ontario. Individuals age 12 to 27 years with a new diagnosis of acne by a general practitioner were identified as belonging to 1 of 5 socioeconomic groups based on median annual neighborhood household income. Patients were then observed for 2 years after the index visit to identify visits to a dermatologist. The main outcome measure was visitation to a dermatologist within 2 years of an initial diagnosis of acne.

RESULTS

The study cohort consisted of 295,469 patients given a diagnosis of acne by their primary care physician of which 59,799 (20%) were subsequently referred to a dermatologist. Of those in the lowest income group of less than Can dollars 20,000, 17% were referred to a dermatologist, as compared with 24% in the highest income group of greater than Can dollars 80,000 (P value for trend < .001). Furthermore, patients living in an urban area had a 43% greater likelihood of being referred to a dermatologist (odds ratio 1.43, 95% confidence interval 1.39-1.48) as compared with patients in a rural location.

LIMITATIONS

Limitations of our study include imputing socioeconomic status of patients on the basis of median income at the neighborhood level rather than on the basis of data on individual patients. Furthermore, our use of administrative databases did not allow us to characterize the severity of acne in our population cohort and whether that would affect referral patterns.

CONCLUSION

Within Canada's universal health care system, those likely to be in lower socioeconomic groups are significantly less likely to visit a dermatologist for specialist consultation.

Dermatology postgraduate training in Canada: CanMEDS competencies

Medical residency education and the development of formalized training objectives in Canada have evolved continuously, especially with the introduction of the Canadian Medical Education Directions for Specialists (CanMEDS) competencies by the Royal College of Physicians and Surgeons of Canada (RCPSC) in 1996. In order to evaluate the effectiveness of implementation of CanMEDS competencies in Canadian postgraduate dermatology training programs from the residents' perspective, a comprehensive national survey of all Canadian core dermatology residents was conducted in June 2004. One hundred percent of core (PGY3-5) dermatology residents across the country (n = 48) completed the survey. Forty eight percent of residents were familiar with the CanMEDS competencies. Within the CanMEDS framework, the competencies were felt to be taught adequately by the following proportion of residents: medical expert (78 %), professional (66 %), communicator (52 %), collaborator (48 %), health advocate (48 %), scholar (48 %), and manager (28 %), with notable differences based on the year of training. This is the first national Canadian survey examining dermatology postgraduate education from the residents' perspective with a focus on CanMEDS competencies. While the RCPSC CanMEDS project implementation is presently in the faculty development phase, further work must be accomplished to enhance awareness of CanMEDS competencies and to incorporate these into dermatology residency programs across the country. Particular targeting of the roles perceived to be poorly taught is needed.

Fulfilling an Unmet Need in Psoriasis

Psoriasis is a chronic inflammatory disease of the skin affecting approximately 2% of the world's population. Traditional systemic treatments, including methotrexate, ciclosporin, psoralen plus UVA (PUVA), oral retinoids and fumaric acid esters, are widely used for severe disease and are effective in the short term. Severe psoriasis is a chronic disease and patients and physicians have expressed concerns about possible harm from organ toxicity, such as skin cancer (PUVA), hyperlipidaemia (retinoids), renal (ciclosporin) or hepatotoxicity (methotrexate). Long-term monitoring is required and may not detect early organ damage. The pathophysiology of psoriasis remains to be clarified, but advances toward the understanding of the immunological basis of psoriasis have uncovered the involvement of immunological pathways; for example, the role of tumour necrosis factor (TNF)-alpha, T cell proliferation and T cell activation, and migration to the epidermis. This advancement in knowledge combined with developments in recombinant technologies has led to the development of target-specific therapies. Biological agents are defined as proteins that can be extracted from animal tissue or produced via recombinant DNA technologies and possess pharmacological activity. Adalimumab, alefacept, infliximab, efalizumab and etanercept are examples of biological agents currently used for the treatment of psoriasis. Some of these are also therapy for other autoimmune conditions, such as rheumatoid arthritis and Crohn's disease. These biological agents are effective in psoriasis but raise new safety concerns. Information on the safety of biological agents in conditions such as rheumatoid arthritis and Crohn's disease can not be directly extrapolated to psoriasis. An increased incidence of lymphomas has been postulated to be associated with etanercept, infliximab and adalimumab; serious infections, such as tuberculosis, have also been reported with these three biologicals, all of which target TNF-alpha. Demyelinating disorders, such as multiple sclerosis, have been reported with some biologicals as has congestive heart failure. Alefacept, because of its mechanism of action of lowering the number of active T cells, is associated with low T cell counts. Efalizumab has been associated with thrombocytopenia and haemolytic anaemia. Data on the safety of >2.5 years' continuous treatment with efalizumab are reassuring and a valuable beginning to understanding the role and risk of harm of long-term therapy for a chronic disease. Longer follow-up studies and safety databases, for each of the biologicals used in psoriasis, are needed to ensure both prolonged efficacy and minimal risk of harm.

Clindamycin skin testing has limited diagnostic potential

We examined the role of clindamycin prick and intradermal skin testing in a tertiary care clinic population. Experience with diagnostic modalities such as prick and intradermal testing has been limited with clindamycin. A retrospective chart review was conducted for patients with immunologic reactions temporally associated with clindamycin who were referred to the Drug Safety Clinic (Toronto, Ontario). A total of 31 patients were identified who had undergone prick and intradermal skin testing. All 31 negative immediate prick and intradermal tests were followed by a 150 mg oral dose of clindamycin. 10/31 (32%) subjects had significant reactions to the oral clindamycin provocation. 2 patients reported delayed reactions at the clindamycin intradermal test sites. Our experience suggests that prick and intradermal skin testing is not adequate in identifying patients with previous allergic reactions associated with clindamycin. Oral provocation tests can be used in patients with histories of clindamycin adverse reactions; however, it should be offered on a risk-benefit basis.

National Appraisal of Dermatology Residency Training

OBJECTIVES

To provide the first comprehensive assessment of dermatology residency training in Canada based on the residents' perspective; to examine and elucidate trends in current residents' envisioned career paths and aspirations.

DESIGN

A national survey conducted in June 2004.

PARTICIPANTS

All Canadian dermatology residents.

MAIN OUTCOME MEASURES

Cross-sectional analysis of (1) satisfaction with and importance placed by the trainees on the various curriculum components as measured by a 5-point Likert-type scale and (2) current residents' career and practice plans.

RESULTS

One hundred percent of dermatology residents across the country (n = 48) responded to the survey. The greatest discrepancies between ranked importance and corresponding satisfaction were observed for the teaching from faculty (both didactic and clinic based) and for the practice management exposure and training. Residents were most satisfied with dermatopathology education (score, 4.4 of 5.0) and least satisfied with cosmetic dermatology (2.7 of 5.0) and dermoscopy training (2.8 of 5.0). Men indicated more interest than women in academics (71% [n = 12] vs 45% [n = 14]), research (41% [n = 7] vs 16% [n = 5]), and teaching (71% [n = 12] vs 42% [n = 13]), while female residents were more inclined toward pediatric dermatology (42% [n = 13] vs 29% [n = 5]) and cosmetic dermatology (48% [n = 15] vs 29% [n = 5]). An overall trend of decreased interest in academic and hospital-based practice was noted with progression through residency training.

CONCLUSIONS

This study provides a current picture of dermatology postgraduate education in Canada from the residents' perspective. Above all, dermatology residents desire more teaching (clinic, didactic, and practice management) and mentorship from their faculty. Recruitment and retention of women in academic dermatology may benefit from early intervention during residency. The data are intended to assist dermatology programs with development, evaluation, and improvement of their curricula and can serve as a reference point to gauge future trends.

Hydrochlorothiazide-Induced Noncardiogenic Pulmonary Edema: An Underrecognized Yet Serious Adverse Drug Reaction

Noncardiogenic pulmonary edema is a rare but potentially life-threatening complication of hydrochlorothiazide therapy. We describe three patients who developed this serious adverse reaction. A 64-year-old woman developed dypsnea and hypotension within 60 minutes of taking a single dose of hydrochlorothiazide 25 mg. She was admitted to the critical care unit with acute respiratory failure and subsequent multiple-organ dysfunction. The second patient was a 56-year-old woman who experienced sudden onset of shortness of breath that developed 10 minutes after taking a single dose of hydrochlorothiazide 25 mg. The third was a 59-year-old woman who developed sudden onset of shortness of breath, nausea, vomiting, and diarrhea after her first dose of hydrochlorothiazide-triamterene. All three women had a history of a similar, albeit minor, reaction to a thiazide diuretic. Review of the literature identified 36 additional cases of noncardiogenic pulmonary edema after thiazide use. The patients developed symptoms 10-150 minutes after ingestion of hydrochlorothiazide or another thiazide. Symptoms can occur on first exposure to the drug or in patients taking the drug intermittently. Of interest, 90% of documented cases occurred in women. With the increasing use of thiazide diuretics in the treatment of hypertension, clinicians need to be aware of the possible association of these drugs with the development of noncardiogenic pulmonary edema.

Adverse drug interactions and reactions in dermatology: current issues of clinical relevance

This article highlights several adverse drug interactions and reactions relevant to current dermatologic practice. Absorption interactions between drugs and compounds containing polyvalent cations, potential interactions between herbal and conventional medicines, the meaning of sulfa allergy, and adverse cutaneous reactions caused by epidermal growth factor receptor inhibitors are discussed.

Clinical and immunogenetic correlates of abacavir hypersensitivity

A patch test (PT) may be useful in defining true abacavir hypersensitivity syndrome (AHS). Seven previously PT-positive patients remote from the original AHS were shown to have robust 24 h responses, supporting PT durability. HLA-B*5701 was present in all seven PT-positive versus one of 11 controls tolerating abacavir (P < 0.001). Five of seven PT (71%) versus one of 11 controls (9%) (P = 0.005) showed significant abacavir-specific CD8 proliferation, suggesting a direct role for HLA-B*5701-restricted CD8 cells in the pathophysiology of AHS.

Integrating Biologic Agents into Management of Moderate-to-Severe Psoriasis: A Consensus of the Canadian Psoriasis Expert Panel

BACKGROUND

Approximately 2% of people worldwide have psoriasis, with as many as 1 million people with psoriasis in Canada alone.1,2 The severity of psoriasis ranges from mild to severe. It can lead to substantial morbidity and psychological stress and have a profound negative impact on patient quality of life.3,4 Although available therapies reduce therapies reduce the extent and severity of the disease and improve quality of life,3 reports have indicated a patient preference for more aggressive therapy and a dissatisfaction with the effectiveness of current treatment options.5

OBJECTIVE

A Canadian Expert Panel, comprising Canadian dermatologists, convened in Toronto on 27 February 2004 to reach a consensus on unmet needs of patients treated with current therapies and how to include the pending biologic agents in and improve the current treatment algorithm for moderate-to-severe psoriasis. Current treatment recommendations suggest a stepwise strategy starting with topical agents followed by phototherapy and then systemic agents.3,6,7 The Panel evaluated the appropriate positioning of the biologic agents, once approved by Health Canada, for the treatment of moderate-to-severe psoriasis.

METHODS

The Panel reviewed available evidence and quality of these data on current therapies and from randomized, controlled clinical trials.8-14 Subsequently, consensus was achieved by small-group workshops followed by plenary discussion.

RESULTS

The Panel determined that biologic agents are an important addition to therapies currently available for moderate-to-severe psoriasis and proposed an alternative treatment algorithm to the current step wise paradigm.

CONCLUSION

The Panel recommended a new treatment algorithm for moderate-to-severe psoriasis whereby all appropriate treatment options, including biologic agents, are considered together and patients' specific characteristics and needs are taken into account when selecting the most appropriate treatment option.

Topical calcineurin inhibitors in the treatment of atopic dermatitis: a meta-analysis of current evidence

PURPOSE

To summarize success rates of the topical calcineurin inhibitors tacrolimus and pimecrolimus in treating atopic dermatitis.

METHODS

Randomized controlled trials (RCTs) comparing either drug to themselves (i.e. dose-ranging studies), each other, the vehicle (or placebo), or corticosteroids were obtained from Medline, EMBASE, and Cochrane databases. Two reviewers identified studies and extracted data, a third reviewer adjudicated disagreements. Outcomes included success, as defined by 90%, 75%, or 50% reductions from baseline in Eczema Area and Severity Index (EASI) scores or equivalent at 1, 3, 6, and 12 months, and also the difference between drug and vehicle (placebo). Rates were combined using a random effects meta-analytic model.

RESULTS

Of 180 articles identified, 165 were rejected (142 not RCTs/inappropriate outcome, 23 inappropriate/unextractable data). We included 15 articles reporting on 16 trials (nine tacrolimus and seven pimecrolimus trials) involving a total of 5301 patients, of whom 2107 received tacrolimus, 1225 received pimecrolimus and 1969 patients were controls. Tacrolimus reduced EASI scores by 65.6% at 1 month and 73.0% at 3 months; pimecrolimus reduced scores by 61.5% at 1 month, 60.3% at 6 months, and 61.9% at 12 months. When the difference in EASI score reductions were compared between active drug and placebo, tacrolimus success was 51.5% above placebo at 1 month and pimecrolimus was 45.9% higher at 1 month, 24.9% at 6 months, and 16.1% at 12 months.

CONCLUSIONS

Success rates for tacrolimus and pimecrolimus were statistically similar. However, tacrolimus rates were consistently higher numerically than those for pimecrolimus, and tacrolimus was used in patients with more severe disease. A head-to-head RCT is required to determine if true differences exist between these drugs.

Psoriasis and the new biologic agents: interrupting a T-AP dance

Psoriasis is an immune-mediated skin disease in which chronic T-cell stimulation by antigen-presenting cells (APC) occurs in the skin. This interplay between the T-cell and APC has been likened to a "T-AP dance" where specific steps must occur in sequence to result in T-cell activation and the disease phenotype; otherwise T-cell anergy would occur. Several novel engineered proteins designed to block specific steps in immune activation (biologic agents) have demonstrated efficacy in the treatment of psoriasis. These agents include fusion proteins, monoclonal antibodies and recombinant cytokines. These medications act at specific steps during the T-AP dance either to inhibit T-cell activation, costimulation and subsequent proliferation of T-cells, lead to immune deviation or induce specific cytokine blockades. The potential increased selectivity for specific pathways in immune activation, clinical efficacy and relative safety of these new agents offers an alternative for the treatment of moderate to severe psoriasis.

Intravenous immunoglobulin: use in dermatology

A manufactured blood product derived from fractionated human plasma, intravenous immunoglobulin (i.v.Ig) contains supra-physiologic levels of IgG. i.v.Ig is currently used in the treatment of immunodeficiency syndromes, inflammatory disorders and infections diseases. Uncontrolled clinical studies and anecdotal case reports recommend its use in dermatology, but randomized clinical trials are lacking. In selecting the most appropriate i.v.Ig for the patient, convenience, efficacy, safety and tolerability of the different products should be considered. With several measures in place to ensure its safety, i.v.Ig offers new hope for the treatment of many severe dermatologic conditions.