Dapsone hypersensitivity. The sulfone syndrome revisited

Overview and Current Advances in Dapsone Hypersensitivity Syndrome

PURPOSE OF REVIEW

As a sulfone antibacterial agent, dapsone has been widely used to treat leprosy. Moreover, dapsone is also used in many immune diseases such as herpetic dermatitis because of its anti-inflammatory and immunomodulatory effects. However, dapsone can cause several adverse effects, the most serious being dapsone hypersensitivity syndrome. Dapsone hypersensitivity syndrome is characterized by a triad of eruptions, fever, and organ involvement, which limits the application of dapsone to some extent.

RECENT FINDINGS

In this article, we review current research about the interaction model between HLA-B*13:01, dapsone, and specific TCR in dapsone-induced drug hypersensitivity. In addition to the proposed mechanisms, we also discussed clinical features, treatment progress, prevalence, and prevention of dapsone hypersensitivity syndrome. These studies reveal the pathogenesis, clinical features, and prevalence from the perspectives of genetic susceptibility and innate and adaptive immunity in dapsone hypersensitivity syndrome, thereby guiding clinicians on how to diagnose, prevent, and treat dapsone hypersensitivity syndrome.

Genetic Diversity of HLA Class I and Class II Alleles in Thai Populations: Contribution to Genotype-Guided Therapeutics

Human leukocyte antigen (HLA) class I and II are known to have association with severe cutaneous adverse reactions (SCARs) when exposing to certain drug treatment. Due to genetic differences at population level, drug hypersensitivity reactions are varied, and thus common pharmacogenetics markers for one country might be different from another country, for instance, HLA-A*31:01 is associated with carbamazepine (CBZ)-induced SCARs in European and Japanese while HLA-B*15:02 is associated with CBZ-induced Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) among Taiwanese and Southeast Asian. Such differences pose a major challenge to prevent drug hypersensitivity when pharmacogenetics cannot be ubiquitously and efficiently translated into clinic. Therefore, a population-wide study of the distribution of HLA-pharmacogenetics markers is needed. This work presents a study of Thai HLA alleles on both HLA class I and II genes from 470 unrelated Thai individuals by means of polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) in which oligonucleotide probes along the stretches of HLA-A, -B, -C, -DRB1, -DQA1, and -DQB1 genes were genotyped. These 470 individuals were selected according to their regional locations, which were from North, Northeast, South, Central, and a capital city, Bangkok. Top ranked HLA alleles in Thai population include HLA-A*11:01 (26.06%), -B*46:01 (14.04%), -C* 01:02 (17.13%), -DRB1*12:02 (15.32%), -DQA1*01:01 (24.89%), and -DQB1*05:02 (21.28%). The results revealed that the distribution of HLA-pharmacogenetics alleles from the South had more HLA-B75 family that a typical HLA-B*15:02 pharmacogenetics test for SJS/TEN screening would not cover. Besides the view across the nation, when compared HLA alleles from Thai population with HLA alleles from both European and Asian countries, the distribution landscape of HLA-associated drug hypersensitivity across many countries could be observed. Consequently, this pharmacogenetics database offers a comprehensive view of pharmacogenetics marker distribution in Thailand that could be used as a reference for other Southeast Asian countries to validate the feasibility of their future pharmacogenetics deployment.

Thermoanalytical investigation of some sulfone-containing drugs

The thermal behavior of some sulfone-containing drugs, namely, dapsone (DDS), dimethylsulfone (MSM), and topiramate (TOP) in drug substances, and products were investigated using different thermal techniques. These include thermogravimetry (TGA), derivative thermogravimetry (DTG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The thermogravimetric data allowed the determination of the kinetic parameters: activation energy (E(a)), frequency factor (A), and reaction order (n). The thermal degradation of dapsone and topiramate was followed a first-order kinetic behavior. The calculated data evidenced a zero-order kinetic for dimethylsulfone. The relative thermal stabilities of the studied drugs have been evaluated and follow the order DDS > TOP > MSM. The purity was determined using DSC for the studied compounds, in drug substances and products. The results were in agreement with the recommended pharmacopoeia and manufacturer methods. DSC curves obtained from the tablets suggest compatibility between the drugs, excipients and/or coformulated drugs. The fragmentation pathway of dapsone with mass spectrometry was taken as example, to correlate the thermal decomposition with the resulted MS-EI. The decomposition modes were investigated, and the possible fragmentation pathways were suggested by mass spectrometry.

Association of human herpesvirus 6 reactivation with the flaring and severity of drug-induced hypersensitivity syndrome

BACKGROUND

Drug-induced hypersensitivity syndrome (DIHS) is an adverse reaction with clinical signs of fever, rash and internal organ involvement. In the vast majority of patients in Japan, the causative drugs for DIHS are limited to the following eight: carbamazepine, phenytoin, phenobarbital, zonisamide, mexiletine, dapsone, salazosulfapyridine and allopurinol. The association of human herpesvirus (HHV)-6 reactivation with DIHS has been reported by various groups.

OBJECTIVES

To confirm the relationship between the flaring and severity of DIHS and HHV-6 reactivation.

METHODS

We evaluated 100 patients with drug rash and systemic symptom(s) caused by the drugs associated with DIHS. HHV-6 reactivation was examined by serological antibody assay and quantitative real-time polymerase chain reaction assay of serial serum samples.

RESULTS

Anti-HHV-6 IgG titres increased in 62 of 100 patients, 14-28 days after the onset of symptoms. These patients suffered from severe organ involvement and a prolonged course compared with 38 patients showing no reactivation of HHV-6. Significant amounts of HHV-6 DNA were detected in serum samples from 18 of the 62 patients. Flaring of symptoms such as fever and hepatitis was closely related to HHV-6 reactivation in these 18 patients. It should be emphasized that all five patients with fatal outcome and 10 patients with renal failure were in the HHV-6 reactivation group.

CONCLUSIONS

A combination of immunological reaction to a drug and HHV-6 reactivation results in the severe course of DIHS. The demonstration of HHV-6 reactivation is a useful marker of diagnosis as well as prognosis in DIHS.

Life-threatening acute adverse cutaneous drug reactions

Adverse cutaneous reactions to drugs are frequent, affecting 2% to 3% of all hospitalized patients. Fortunately, only about 2% of adverse cutaneous reactions are severe and very few are fatal. Stevens-Johnson syndrome and toxic epidermal necrolysis are severe life-threatening diseases with a mortality rate reaching 30%, and only prompt recognition and diagnosis, withdrawal of the offensive drug, and referral to an intensive care unit or burn care unit might improve the prognosis and save the patient's life. Drug eruption with eosinophilia and systemic symptoms syndrome, formerly termed drug hypersensitivity syndrome, is a rather distinct severe adverse drug reaction (ADR) characterized by eruption, fever, lymph node enlargement, and single or multiple organ involvement, with a high morbidity and a mortality rate of 10%. These severe ADRs, together with serum sickness-like syndrome, are discussed in this review. Other severe reactions, such as anaphylaxis and vasculitis, are discussed elsewhere in this issue. Although most of the readers, particularly those in the outpatient arena, will not be treating these patients, they are the ones who will see them first, diagnose them, realize the potential danger in their condition, and refer them to the appropriate treatment venue. Therefore, dermatologists should be familiar with these conditions and be prepared to handle them adequately.

Drug-induced severe skin reactions. Incidence, management and prevention

Severe skin adverse drug reactions can result in death, but the rate of such events is fortunately low. The incidences of Stevens-Johnson syndrome and toxic epidermal necrolysis range from 1.2 to 6 per million per year and 0.4 to 1.2 per million per year, respectively. Stevens-Johnson syndrome is fatal in about 5% and toxic epidermal necrolysis in 30% of cases. Drugs implicated in these diseases are the sulphonamides, anticonvulsants, allopurinol, pyrazolone derivatives, oxicams and chlormezanone. The principles of symptomatic treatment are the same as for burns, and patients with extensive skin detachment should be transferred to an intensive care unit or a burn centre. Hypersensitivity syndrome is characterised by mucocutaneous eruption and fever with frequent lymphadenopathy, hepatitis and eosinophilia. Drugs implicated are mainly anticonvulsants and sulphonamides. The mortality rate of such a reaction has been estimated to be about 8%. Corticosteroid therapy has been widely used in hypersensitivity syndrome, despite the lack of controlled studies. Drug-induced vasculitis and serum sickness may also be life-threatening when the kidney, liver, gastrointestinal tract or nervous system are involved. In angioedema, congestion may involve mucous membranes and therefore impair swallowing and ventilation. Drugs associated with angioedema include penicillins, radiographic contrast agents and ACE inhibitors. Severe forms of angioedema necessitate epinephrine (adrenaline) subcutaneous injection and possibly resuscitative efforts. Corticosteroids and/or antihistamines are used to block or reduce prolonged or late phase reactions. Prompt recognition and withdrawal of the suspected drug is essential in severe drug-induced skin reactions.

A case of the 'dapsone syndrome'

The 'dapsone syndrome' developed in a 44-year-old woman who was treated for pyoderma gangrenosum with 100 mg/day dapsone for about 5 weeks. Symptoms included fever, malaise, jaundice with hepatic dysfunction, lymphadenopathy, mononucleosis and dermatitis. These symptoms disappeared with 30 mg/day of oral prednisolone. A lymphocyte stimulation test with dapsone was positive, as was the delayed-type intradermal skin test with 0.5 and 0.05% dapsone in saline. Immunohistochemical studies of the rash and skin test reaction revealed that the dominant infiltrating T cells in the upper dermis were of the Leu 2a+ cytotoxic/suppressor-type rather than the Leu 3a+ helper/delayed hypersensitivity-type.