Cutaneous drug eruptions: a 5-year experience

Drug hypersensitivity and eosinophilia: The decisive role of p-i stimulation

Eosinophilia is a common finding in drug hypersensitivity reactions (DHR). Its cause is unclear, as neither antigen/allergen-driven inflammation nor clonal expansion is involved. Most delayed-DHRs are due to p-i (pharmacologic interaction of drugs with immune receptors). These are off-target activities of drugs with immune receptors that result in various types of T-cell stimulation, some of which involve excessive IL-5 production. Functional and phenotypic studies of T-cell clones and their TCR-transfected hybridoma cell lines revealed that some p-i-induced drug stimulations occur without CD4/ CD8 co-receptor engagement. The CD4/CD8 co-receptors link Lck (lymphocyte-specific protein tyrosine kinase) and LAT (linker for activation of T cells) to the TCR. Alteration of Lck or LAT can result in a TCR signalosome with enhanced IL-5 production. Thus, if a more affine TCR-[drug/peptide/HLA] interaction allows bypassing the CD4 co-receptor, a modified Lck/LAT activation may lead to a TCR signalosome with elevated IL-5 production. This "IL-5-TCR-signalosome" hypothesis could also explain eosinophilia in superantigen or allo-stimulation (graft-versus-host disease), in which evasion of CD4/CD8 co-receptors has also been described. It may open new therapeutic possibilities in certain eosinophilic diseases by directly targeting the IL-5-TCR signalosome.

The role of eosinophils in the differential diagnosis of inflammatory skin diseases

Eosinophils are known to be present in inflammatory skin diseases, but their diagnostic utility is not well established. Upon review of the published status of lesional eosinophils, several categories were identified. 1) Lesional eosinophils highly characteristic such that, in their absence, the pathologist may question the diagnosis. These include arthropod bite reactions and scabies, urticarial dermatitis, and other eosinophilic dermatoses. 2) Lesional eosinophils rare or absent, such that, in their presence, the pathologist may question the diagnosis. These include pityriasis lichenoides, graft versus host disease, and connective tissue disorders. 3) Lesional eosinophils variable and, while in some cases expected, are not required for diagnosis. These include drug reactions, atopic dermatitis and allergic contact dermatitis. 4) Lesional eosinophils variable and not expected but may be seen to a limited extent. These include lichen planus and psoriasis.

Disorders of Facial Hyperpigmentation

Disorders of hyperpigmentation are common and challenging conditions which can arise due to a myriad of etiologic factors. Many of them can present across skin types but are more common in skin of color individuals with Fitzpatrick skin types III-VI. Facial hyperpigmentation, in particular, can have a significant impact on the quality of life of affected individuals due to its increased visibility. This article provides a comprehensive review of disorders of facial hyperpigmentation including epidemiology, pathogenesis, diagnostic considerations, and treatment approaches for these conditions.

Drug fever: a narrative review

Drug fever is an adverse drug reaction accompanied by a febrile response and is a common problem among clinicians, hence an updated knowledge of drug fever is important. A consensus regarding the definition of drug fever is lacking. Thus, descriptions of drug fever in previous literature are often inconsistent. In this narrative review, we summarized various features of drug fever, including its definition, epidemiology, risk factors, clinical presentation, diagnosis, treatment and prognosis, based on the earliest literature. Recent advances in information technology have encouraged researchers to use pharmacovigilance databases for clinical and pharmacological research. We outlined how a pharmacovigilance database, along with recently developed research methods, could be used to research drug fever.

Skin of colour: essentials for the non-dermatologist

Doctors-in-training often receive an inadequate dermatology education. Furthermore, studies have highlighted the under-representation of skin of colour (SOC) in dermatological teaching, learning resources and research. Our image-based questionnaire, distributed to all internal medicine trainees in southwest England, highlighted knowledge gaps regarding SOC among training physicians. It is intrinsically more challenging for clinicians to confidently formulate dermatological diagnoses in SOC. In this review, we provide guidance for physicians to help make the diagnostic process more straightforward. First, we outline how skin colour is determined and classified. We discuss how inflammation presents in SOC, with the typical 'erythema' that physicians often associate with inflammation being a less prominent feature in darker skin tones. We then summarise nine important conditions that we believe physicians working in all specialties should be able to identify in patients with SOC, covering both conditions encountered on the medical take and conditions disproportionately affecting individuals with SOC. The population of the UK is rapidly diversifying; thus, as physicians, we have a professional duty to educate ourselves on dermatological conditions in SOC to provide the best quality of care for all our patients, regardless of their skin type.

The Mixed Spongiotic and Interface Reaction Pattern: A Study of Clinical and Histopathologic Findings

BACKGROUND

Categorization of biopsy specimens into inflammatory reaction patterns is central to dermatopathologic assessment. Mixed inflammatory patterns are poorly characterized and may represent clinicopathologic challenges. The purpose of this study was to identify clinical and histopathologic findings associated with the mixed spongiotic-interface dermatitis (SID) histopathologic pattern.

METHODS

Fifty-one institutional biopsy specimens of SID were identified over a 2-year period by retrospective natural language search. Histopathologic and clinical features were identified.

RESULTS

The most common histopathologic features associated with SID were mild spongiosis (51%), focal vacuolar interface change (72%), lymphocytic exocytosis (92%), and superficial-dermal lymphocytic infiltrate (94%) with variable eosinophils (61%). Clinically, 80% of subjects presented with a symmetric morbilliform eruption. Polypharmacy (94%), immunosuppression (47%), and history of malignancy (47%) were common. The most common diagnoses were drug reaction (37%), possible drug reaction (12%), and viral exanthem (12%). Drug reaction with eosinophilia and systemic symptoms represented 25% of all confirmed cutaneous adverse drug reactions (CADR). Average time from drug initiation to symptom initiation was 20 days (SD: 22.3, range: 0-90); median disease duration was 25.5 days. Spongiotic vesicles and Langerhans cells were less common in patients with a strong clinicopathologic diagnosis of drug reaction compared to non-drug eruptions (p = 0.04).

CONCLUSIONS

The mixed SID pattern is commonly encountered in CADR but may represent a more subacute course, implying consideration for inciting medication(s) started before the typical 7- to 14-day window.

Histopathologic Features of Maculopapular Drug Eruption

Background: Cutaneous adverse drug reaction (CADR) is common in both inpatient and outpatient clinical settings and has been associated with a large variety of medications. Drug reactions represent a significant burden to the healthcare system due to increased hospital stay durations and associated costs. Moreover, some of these reactions may be life-threatening. The most common clinical manifestation of a CADR is a maculopapular drug eruption (MDE). Due to its many clinical mimics and associations with a variety of histopathologic patterns, maculopapular drug eruption is difficult to definitively diagnose from both a clinical and histopathological perspective. Summary: We reviewed the clinical and histopathologic features of 327 cases of MDE from several studies in the literature and summarized characteristic histopathologic findings and their frequencies of occurrence. We found that the most common and suggestive histopathologic features of MDE were epidermal spongiosis, lymphocytic infiltrate, and occasional necrotic keratinocytes; interface change at the DEJ; superficial perivascular and interstitial lymphocytic infiltrate with or without eosinophils and neutrophils in the mid-to-deep dermis and mild papillary dermal edema; and dilation of superficial vessels. The presence of multiple histopathologic patterns within the same tissue specimen is also suggestive of MDE. This review and analysis suggest that a biopsy may improve the diagnostic accuracy by both establishing common and uncommon features associated with MDE and reviewing features that help to exclude other causes of maculopapular eruption. Key Message: Histopathologic criteria for the diagnosis of MDE, while not entirely specific, may aid in establishing a differential that includes a drug eruption. Thus, a biopsy can be a helpful diagnostic tool when MDE is suspected by demonstrating findings suggestive of MDE or by ruling out clinical mimics. However, biopsy results cannot be used in isolation as clinical-pathologic correlation is paramount in MDE.

Skin eruptions in children: Drug hypersensitivity vs viral exanthema

Childhood rashes or exanthemas are common and are usually relatively benign. There are many causes of rash in children, including mainly viruses, and less often bacterial toxins, drugs, allergens and other diseases. Viral exanthema often appears while children are taking a medication in the course of a viral infection; it can mimic drug exanthema and is perceived as a drug allergy in 10% of cases. In the vast majority of cases, the distinction between virus-induced and drug-induced skin eruption during the acute phase is not possible. The drugs most commonly implicated are beta-lactams (BL) and non-steroidal anti-inflammatory drugs (NSAIDs). Viruses, commonly Epstein-Barr virus (EBV), human herpesvirus 6 (HHV6) and cytomegalovirus (CMV), and the bacterium, Mycoplasma pneumoniae, may cause exanthema either from the infection itself (active or latent) or because of interaction with drugs that are taken simultaneously. Determination of the exact diagnosis requires a careful clinical history and thorough physical examination. Haematological and biochemical investigations and histology are not always helpful in differentiating between the two types of exanthema. Serological and polymerase chain reaction (PCR) assays can be helpful, although a concomitant acute infection does not exclude drug hypersensitivity. A drug provocation test (DPT) is although considered the gold standard for the diagnosis and is not preferred by the patients. Skin tests are not well tolerated, and in vitro tests, such as the basophil activation test and lymphocyte transformation, are of low sensitivity and specificity and their relevance is debatable. Based on current evidence, we propose a systematic clinical approach for timely differential diagnosis and management of rashes in children who present a cutaneous eruption while receiving a drug.

[Emergencies in dermatology : From gonorrhea to angioedema]

The spectrum of dermatological emergencies is diverse. Infections, in particular sexually transmitted infections, anaphylactic reactions, and cutaneous drug reactions are common causes for patients to present themselves to the dermatological emergency service. If a sexually transmitted infection is suspected, it is important for the physician to recognize which diseases need immediate treatment to avoid late complications. This requires a reliable diagnosis and knowledge of the appropriate therapy. Cutaneous drug reactions can take many forms. There is a spectrum of reactions that occur immediately after the administration of a medication (which manifest themselves as anaphylaxis), to those that can appear weeks after the initiation of a therapy. These reactions can be harmless and self-limiting, but also be life-threatening. It is essential for physicians in everyday clinical practice to recognize drug intolerances in time and to treat them appropriately.

Cutaneous adverse drug reactions in patients with peripheral blood eosinophilia during antituberculosis treatment

BACKGROUND/AIMS

Peripheral eosinophilia during tuberculosis (TB) treatment is common, but has not been fully evaluated. The aim of this study was to determine the prevalence and clinical significance of peripheral blood eosinophilia in patients undergoing anti-TB treatment.

METHODS

We retrospectively reviewed the clinical and laboratory data of patients who received anti-TB treatment and had peripheral blood eosinophilia (> 5% of the total white blood cell count) at the Chonnam National University Hospital between January 2010 and December 2014.

RESULTS

Of all 2,234 patients with TB who received anti-TB treatment, 397 (17.8%) had peripheral blood eosinophilia. Of the 397 with eosinophilia, we reviewed the data of 262 (66%), and cutaneous adverse drug reactions (CADRs) were observed in 161 (61.5%). Of the 161 with CADRs, itching (47.2%) and skin rash (47.8%) were common. Older age, abnormal liver function, and higher peak blood eosinophil percentage were associated with CADRs in multivariate analysis. There was a significant relationship between increased peak eosinophil counts and the degree of severity of CADRs.

CONCLUSION

Peripheral blood eosinophilia is a relatively common occurrence during anti-TB treatment. Peripheral blood eosinophil counts were higher according to the degree of severity of CADRs.

Dermatologic Conditions of the Early Post-Transplant Period in Hematopoietic Stem Cell Transplant Recipients

Hematopoietic stem cell transplants (HSCTs) are used to treat a variety of conditions, including hematologic malignancies, bone marrow failure syndromes, and immunodeficiencies. Over 60,000 HSCTs are performed annually worldwide, and the numbers continue to increase. Indeed, as new conditioning regimens develop, more and more individuals, including those of older age, will be eligible for transplants. Nevertheless, although HSCTs are clearly a life-saving and necessary treatment for thousands of patients per year, there is still substantial morbidity and mortality associated with the procedure. Of note, skin eruptions in the post-HSCT period are frequent and often significantly reduce quality of life in recipients. Moreover, these cutaneous findings sometimes herald an underlying systemic condition, presenting possible opportunities for timelier intervention. Dermatologists therefore play a vital role in distinguishing life-threatening conditions from benign issues and prompting recognition of critical complications earlier in their course. This article aims to review the major dermatologic conditions occurring in the early post-HSCT period.

[Histopathology of cutaneous drug reactions]

There are many different types of cutaneous adverse reactions. The most classical reactions are driven by T lymphocytes that specifically react towards a drug, with an individual genetic susceptibility linked to certain type I major histocompatibility complex alleles. These reactions are characterized by a wide variety of clinical and histopathological presentations, and a wide range of severity. The most frequent entity is the maculopapular rash, while the most aggressive forms are the Steven-Johnson syndrome and toxic epidermal necrolysis (SJS-TEN). The histopathological alterations associated to each of these syndromes have been better described in the literature during the past 10 years, encompassing non-specific lesions, as in most drug induced maculopapular rashes, to more specific inflammatory patterns. The finding of confluent apoptotic keratinocytes with epidermal detachment is the prototypical aspect of SJS-TEN. There are however numerous pitfalls, and a similar aspect to those observed in each cutaneous drug reactions entities can be found in other diseases. DRESS syndrome can indeed present with dense and epidermotropic T-cell infiltrate, sometimes with nuclear atypias, and thus can be difficult to distinguish from a primary or secondary cutaneous T-cell lymphoma. The diagnosis of cutaneous adverse reactions relies on a clinical-pathological confrontation and requires an accurate evaluation of drug imputability.

Practice Gaps: Drug Reactions

The term "drug reactions" is relevant to dermatology in three categories of reactions: cutaneous drug reactions without systemic features, cutaneous drug reactions with systemic features, and systemic drugs prescribed by the dermatologist with systematic adverse effects. This article uses examples from each of these categories to illustrate several important principles central to drug reaction diagnosis and management. The information presented will help clinicians attain the highest possible level of certainty before making clinical decisions.

Adverse Medication Reactions

Cutaneous adverse drug reactions (ADRs) are among the most frequent adverse reactions in patients receiving drug therapy. They have a broad spectrum of clinical manifestations, are caused by various drugs, and result from different pathophysiological mechanisms. Hence, their diagnosis and management is challenging.

Severe cutaneous ADRs comprise a group of diseases with major morbidity and mortality, reaching 30 % mortality rate in cases of Toxic Epidermal Necrolysis.

This chapter covers the terminology, epidemiology, pathogenesis and classification of cutaneous ADR, describes the severe cutaneous ADRs and the clinical and laboratory approach to the patient with cutaneous ADR and presents the translation of laboratory-based discoveries on the genetic predisposition and pathogenesis of cutaneous ADRs to clinical management guidelines.

Eosinophilic Drug Allergy

While peripheral or tissue eosinophilia may certainly characterize drug eruptions, this feature is hardly pathognomonic for a medication-induced etiology. While delayed drug hypersensitivity reactions with prominent eosinophilic recruitment have been typically classified as type IVb reactions, their pathophysiology is now known to be more complex. Eosinophilic drug reactions have a diversity of presentations and may be benign and self-limited to severe and life-threatening. The extent of clinical involvement is also heterogeneous, ranging from isolated peripheral eosinophilia or single organ involvement (most often the skin and lung) to systemic disease affecting multiple organs, classically exemplified by drug-reaction with eosinophilia and systemic symptoms (DRESS). The spectrum of implicated medications in the causation of DRESS is ever expanding, and multiple factors including drug metabolites, specific HLA alleles, herpes viruses, and immune system activation have been implicated in pathogenesis. Due to this complex interplay of various factors, diagnostic workup in terms of skin and laboratory testing has not been validated. Similarly, the lack of controlled trials limits treatment options. This review also describes other localized as well as systemic manifestations of eosinophilic disease induced by various medication classes, including their individual pathophysiology, diagnosis, and management. Given the multitude of clinical patterns associated with eosinophilic drug allergy, the diagnosis can be challenging. Considerable deficits in our knowledge of these presentations remain, but the potential for severe reactions should be borne in mind in order to facilitate diagnosis and institute appropriate management.

Inpatient Consultative Dermatology

Dermatology consultation can improve diagnostic accuracy in the hospitalized patient with cutaneous disease. Dermatology consultation can streamline and improve treatment plans, and potentially lead to cost savings. Dermatology consultants can be a valuable resource for education for trainees, patients, and families. Inpatient consultative dermatology spans a breadth of conditions, including inflammatory dermatoses,infectious processes, adverse medication reactions, and neoplastic disorders, many of which can be diagnosed based on dermatologic examination alone, but when necessary, bedside skin biopsies can contribute important diagnostic information.

Drug-induced skin reactions: a pathologist viewpoint

Cutaneous drug reactions are common adverse effects that occur in about 2-3% of the hospitalized patients. They have both immunologic and non-immunologic underlying mechanisms. These reactions are clinically and histologically similar to dermatoses. Their significant clinical indicators include: history of drug intake, atypical clinical features and improvement after cessation of the offending drugs. Their diagnostic histological clues include the presence of mixed histological patterns, apoptotic keratinocytes, eosinophils (dermis and epidermis), papillary dermal edema and extravasations of erythrocytes. However, no single clinical or histological feature is specific of drug eruptions. This work attempts to classify the histomorphologic reactions to various drugs in defined categories for assistance in morphologic diagnosis.

Delayed hypersensitivity reaction resulting in maculopapular-type eruption due to entecavir in the treatment of chronic hepatitis B

Several clinical trials have demonstrated the potent antiviral efficacy of entecavir (ETV), and this relatively new nucleoside analogue drug has rapidly become a frequently prescribed therapy for chronic hepatitis B (CHB) worldwide. While the studies have also shown a good overall safety profile for ETV, adverse drug reactions (ADRs) in patients with advanced cirrhosis have been reported and represent a broad spectrum of drug-induced injuries, including lactic acidosis, myalgia, neuropathy, azotemia, hypophosphatemia, muscular weakness, and pancreatitis, as well as immune-mediated responses (i.e., allergic reactions). Cutaneous ADRs associated with ETV are very rare, with only two case reports in the publicly available literature; both of these cases were classified as unspecified hypersensitivity allergic (type I) ADR, but neither were reported as pathologically proven or as evaluated by cytokine release analysis. Here, we report the case of a 45-year-old woman who presented with a generalized maculopapular rash after one week of ETV treatment for lamivudine-resistant CHB. The patient reported having experienced a similar skin eruption during a previous three-month regimen of ETV, for which she had self-discontinued the medication. Histopathological analysis of a skin biopsy showed acanthotic epidermis with focal parakeratosis and a perivascular lymphocytic infiltrate admixed with interstitial eosinophils in the papillary and reticular dermis, consistent with a diagnosis of drug sensitivity. A lymphocyte stimulation test showed significantly enhanced IL-4, indicating a classification of type IVb delayed hypersensitivity. The patient was switched to an adefovir-lamivudine combination regimen and the skin eruption resolved two weeks after the ETV withdrawal. This case represents the first pathologically and immunologically evidenced ETV-induced delayed type hypersensitivity skin reaction reported to date. Physicians should be aware of the potential, although rare, for cutaneous ADRs associated with ETV treatment.

Toxic epidermal necrolysis: Part II. Prognosis, sequelae, diagnosis, differential diagnosis, prevention, and treatment

Toxic epidermal necrolysis (TEN) is a life-threatening, typically drug-induced, mucocutaneous disease. TEN has a high mortality rate, making early diagnosis and treatment of paramount importance. New but experimental diagnostic tools that measure serum granulysin and high-mobility group protein B1 (HMGB1) offer the potential to differentiate early TEN from other, less serious drug reactions, but these tests have not been validated and are not readily available. The mainstay of treatment for TEN involves discontinuation of the offending drug, specialized care in an intensive care unit or burn center, and supportive therapy. Pharmacogenetic studies have clearly established a link between human leukocyte antigen allotype and TEN. Human leukocyte antigen testing should be performed on patients of East Asian descent before the initiation of carbamezapine and on all patients before the initiation of abacavir. The effectiveness of systemic steroids, intravenous immunoglobulins, plasmapheresis, cyclosporine, biologics, and other agents is uncertain.

Adverse cutaneous drug reactions among hospitalized patients: five year surveillance

CONTEXT

Cutaneous Adverse Drug Reactions (CADRs) are observed in 2-3% of hospitalized patients. The clinical presentation of the CADRs varies among different populations.

OBJECTIVE

To study the CADRs in hospitalized patients and their outcome.

MATERIALS AND METHODS

Patients hospitalized at our department between 2005 May and 2010 May were retrospectively reviewed for the diagnosis of CADRs.

RESULTS

A total of 94 patients (3.3%) were diagnosed with CADR among 2801 hospitalized patients. Of them, 56 patients were female (59.6%) and 38 patients were male (40.4%). The culprit drugs were antibiotics (24.5%), non-steroid anti-inflammatory drugs (NSAID) (22.4%), anticonvulsants (13.8%), antihypertensive agents (8.5%), paracetamol with or without pseudoephedrine or phenylephrine (6.4%), intravenous contrasts (3.2%), terbinafine (2.1%), biologic agents (2.1%) and various other medications (17.0%). The most common clinical type of CADRs was morbilliform exanthemas in 59.6% of the patients, followed by erythroderma (6.4%), drug reactions with eosinophilia and systemic symptoms (6.4%), lichenoid drug reaction (5.3%), urticaria and angioedema (4.3%), acute generalized exanthematous pustulosis (4.3%), drug-induced vasculitis (3.2%), drug induced psoriasis (2.1%), Stevens-Johnson syndrome/toxic epidermal necrolysis overlap (2.1%), psoriasiform drug reaction (2.1%). Fixed drug reaction, erythema multiforme, bullous drug reaction, drug induced panniculitis were observed in one each. No deaths occurred on the follow-up. Fever was observed in 35.1% of the patients. Eosinophilia was present in 51.1% of them. Latency period ranged between 0-15 days in 59 patients (62.8%), 15-30 days in 19 patients (20.2%), 30-90 days in 13 patients (13.8%), 90-120 days in three of them (3.2%). The latency for anticonvulsant drugs was statistically longer than the other group of drugs (p: 0.027).

DISCUSSION AND CONCLUSIONS

CADRs were more common in women and most of them were caused by antimicrobial agents followed by NSAIDs and anticonvulsants. Latency period of anticonvulsants were longer than the other groups.

Is drug allergy less prevalent than previously assumed? A 5-year analysis

BACKGROUND

Rashes are a frequent conundrum in clinical practice as they may be reactive, drug induced or disease specific. Identification of the culprit drug is important as re-exposure may be harmful or even life-threatening and unnecessary avoidance of 'innocent' drugs leads to limitations of treatment options.

OBJECTIVE

To objectify the cause of suspected cutaneous drug reactions in a large patient population.

METHOD

Over 5years (2006-10), 612 patients with suspected cutaneous drug reactions were evaluated. Histology was assessed. About 200 patients were invited for complete work-up with skin tests (prick/intracutaneous testing and scratch/patch as indicated) and, if necessary, lymphocyte transformation tests (LTT). In special cases, drug provocation tests were conducted.

RESULTS

A total number of 141 cases with suspected drug reaction underwent full work-up (age 6-86years; 75% female, 25% male). In 107 cases (76%) a drug was identified whereas 34 (24%) were reactive rashes or had other causes. Mostly, cutaneous drug reactions were maculopapular rashes, urticaria/angio-oedema; less frequently, acute generalized exanthematous pustulosis, drug reaction with eosinophilia and systemic symptoms, systemic drug-related intertriginous and flexural exanthema, toxic epidermal necrolysis and fixed drug eruptions were present. Of all the cutaneous drug reactions investigated, 39·8% were caused by antibiotics, 21·2% by anti-inflammatories, 7·6% by contrast media and 31·4% by others (oral antidiabetics, antimycotics, antipsychotics, antiepileptics and others).

CONCLUSION

Clinical assessment overestimates the role of drug allergies in cutaneous reactions. Assessment of suspected drug reactions can be greatly improved by thorough evaluation including dermatological and allergological work-up with skin testing and assays such as LTT.

Cutaneous simulants of infectious disease

Many cutaneous conditions can mimic infection. If these lesions are not accurately recognized, they may be treated with antimicrobial agents, which adds cost, potential risk, and inconvenience to the patient and the healthcare system. The presenting signs and symptoms of many ulcerating, pustular, morbilliform, bullous, neoplastic, granulomatous, autoimmune, and neutrophilic conditions, as well as clinical vasculitis, cellulitis, folliculitis, and panniculitis, have been mistaken for infection. This review emphasizes the clinical presentation, physical exam, and diagnostic workup of many of these conditions to assist the clinician in ascertaining the correct diagnosis. In addition, general treatment options are provided for each disease category.

Natural killer cells and T cells induce different types of skin reactions during recall responses to haptens

The role of T cells in contact hypersensitivity (CHS) to haptens has been well described. However, recent reports demonstrated that CHS-like reactions to experimental haptens could be induced in mice deficient in T cells and B cells, as a result of adaptive-like features of NK cells. Here, we compared hapten-specific inflammatory reactions induced by memory T cells or NK cells. Classical CHS protocols were applied to WT or T- and B-cell deficient mice. Adoptive transfers of hapten-specific T cells and NK cells were also performed. Liver NK cells from hapten-primed mice induced specific recall responses to haptens upon transfer in CD3ε-deficient mice, thus confirming the existence of "memory" NK cells in the liver. We investigated the nature of the inflammation generated in these transfer conditions and found that hapten-induced skin inflammation mediated by CD8(+) T cells or "memory" NK cells are different. Indeed, ear swelling induced by memory NK cells was transient and not associated with cellular infiltrate and inflammation markers, characteristic for T-cell-mediated responses. Thus, NK cells and T cells mediate distinct forms of skin inflammation. NK cell-mediated pathogenesis does not rely on cellular infiltrate and could be involved in atypical forms of adverse drug reactions.

Causality assessment of cutaneous adverse drug reactions

BACKGROUND

Cutaneous adverse drug reactions (ADRs) are the most common adverse reactions attributed to drugs. A systematic and effective approach to a patient with suspected drug eruption allows for prompt recognition, classification and treatment of cutaneous ADRs. A standardized and effective approach for objective causality assessment is necessary to make consistent and accurate identification of ADRs.

OBJECTIVE

Although the Naranjo algorithm is the most widely used assessment tool, it contains many components which are not suitable for clinical assessment of ADRs in Korea. The purpose of this study is to compare correlations of the Naranjo algorithm and the Korean algorithm to evaluate usefulness of both algorithms in order to make a causal link between drugs and cutaneous ADRs. In addition, this study classifies the clinical types and causative agents of cutaneous ADRs.

METHODS

The authors retrospectively reviewed the clinical types and laboratory findings of patients who were diagnosed with cutaneous ADRs in the dermatology clinic at Gil hospital. One hundred forty-one patients were enrolled in this evaluation. The causal relationship of ADRs was assessed by using the Naranjo algorithm and Korean algorithm (version 2.0).

RESULTS

A cross-tabulation analysis was applied to the Naranjo algorithm and Korean algorithm (version 2.0). Simple correlation analysis and a Bland-Altman plot were used for statistical analysis. Correlation analysis confirmed that the two assessment algorithms were significantly correlated. Exanthematous eruptions (68.8%), Stevens- Johnson syndrome (10.6%), and urticaria (8.5%) were the most common types of cutaneoues ADRs. The most common causative agents were antibiotics/antimicrobials, antipyretics/non-steroidal anti-inflammatory drugs, and central nervous system depressants.

CONCLUSION

The Naranjo algorithm and Korean algorithm (version 2.0) were significantly correlated with each other, and thus reliable assessment methods to determine cutaneous ADRs.

Histopathology of drug eruptions - general criteria, common patterns, and differential diagnosis

Drug eruptions are among the most common inflammatory diseases of the skin and also among those biopsied most often. Yet, the value of histopathologic examination of drug eruptions has often been disputed. One reason is that the spectrum of histopathologic changes in drug eruptions is broad. Nevertheless, each histopathologic pattern assumed by drug eruptions has a limited number of differential diagnoses, and numerous criteria and clues are available to distinguish drug eruptions from other diseases associated with those patterns. By recognition of common patterns, consideration of differential diagnoses, and attention to distinct clues, a histopathologic diagnosis of drug eruption can usually be made with confidence.

Cutaneous adverse drug reactions in a hospital-based Chinese population

BACKGROUND

Cutaneous adverse drug reactions (CADRs) are common skin adverse reactions associated with drugs.

AIM

To assess recent trends in CADRs and the drugs associated with them, using data from the past 5 years in the largest single database available on a hospital-based population in China.

METHODS

All clinical records of inpatients admitted with a diagnosis of CADR to the Dermatology Ward, Huashan Hospital from January 2004 to December 2008 were retrospectively studied.

RESULTS

In the 734 patients, the three most common types of CADRs were nonsevere reactions, erythema multiforme (EM)-like eruptions (n = 255), urticaria (n = 192) and exanthematous reactions (n = 159), followed by three severe reactions: Stevens-Johnson syndrome (n = 58), toxic epidermal necrolysis (n = 29) and exfoliative dermatitis (n = 22). The most common single drug associated with the development of all drug eruptions was allopurinol, followed by amoxicillin, cephalosporins, antiepileptic agents and antipyretic/analgesic agents. However, the most common single drugs associated with severe reactions were antiepileptic agents, followed by allopurinol, antipyretic/analgesic agents and cephalosporins. In contrast to patients with nonsevere reactions, patients with severe reactions were more likely to be male (P < 0.001) and to have a greater mean age of onset (P < 0.001), a longer latency period (P < 0.001) and a longer duration of hospitalization (P < 0.001).

CONCLUSION

In contrast to previous studies, we found allopurinol to be the most common single drug associated with CADRs followed by antibiotics (amoxicillin and cephalosporins), and antiepileptic, especially carbamazepine. A higher incidence of EM-like eruptions and urticaria was also seen.