Intraepidermal Pustules Research Articles

Clinical characteristics, treatment and outcome of clindamycin induced acute generalized exanthematous pustulosis.

Acute generalized exanthematous pustulosis (AGEP) is a serious and rare adverse reaction to clindamycin. This study investigated the clinical features of clindamycin-induced AGEP and provided reference for the prevention and treatment of AGEP. Case reports, case series and clinical studies of clindamycin-induced AGEP were collected by retrieving English and Chinese database from inception until May 31, 2024. Of the 35 patients included, 25 (71.4%) were female, and the median age was 57 years (1.6-88 years). The duration of AGEP onset is 2 days (range 0.04,13) after initial administration. The main clinical morphology of AGEP is a non-follicular pustular on an erythematous base, which may be accompanied by fever (54.3%) and pruritus (40.0%). These lesions mainly involved extremities and trunk. The median elevated neutrophil count was 13.3 × 109/L (range 10.3, 31.4). Histologic features of AGEP are characterized by intracorneal, subcorneal, and/or intraepidermal pustules with papillary dermal edema containing neutrophilic, lymphocytic, andeosinophilic infiltrates. Patients gradually recovered after the withdrawal of clindamycin and supportive therapy with a median time of 9 days (range 2, 30). Clinicians should be aware of AGEP as a rare adverse effect of clindamycin. When clindamycin is prescribed, it should be stopped in time when AGEP occurs, and active systemic treatment should be given. AGEP is a self-limiting disease with a good prognosis.

Re-evaluating the prevalence of anti-desmocollin-1 IgA autoantibodies in canine pemphigus foliaceus

Pemphigus foliaceus (PF) is an autoimmune skin disease of dogs characterized by intraepidermal pustules containing neutrophils and dissociated keratinocytes that develop in association with circulating and tissue-bound IgG autoantibodies. A subset of IgG autoantibodies in canine PF target desmocollin-1 (DSC1), a component of intercellular adhesion complexes within the epidermis. Passive transfer of IgG autoantibodies from canine PF sera to mice was previously shown to induce skin disease in the absence of infiltrating neutrophils. In attempts to identify a mechanism responsible for neutrophil recruitment, past studies evaluated the prevalence of IgA autoantibodies in canine PF sera where they were found in <20% of affected dogs. We re-evaluated the prevalence of anti-DSC1 IgA in canine PF due to concerns regarding the sensitivity of previously used methods. We hypothesized that anti-DSC1 IgA are present in most dogs with PF but have been under-detected due to competition with concurrent anti-DSC1 IgG for binding to their mutual antigenic target. Despite removing approximately 80% of IgG from patient sera using affinity chromatography, we did not detect an increase in anti-DSC1 IgA by performing indirect immunofluorescence on canine DSC1-transfected HEK293T cells. Taken together, our results do not support a role for pathogenic IgA in canine PF.

Characterization of cutaneous lesions caused by natural tick infestation in cattle.

Although tick infestation is a significant health problem in livestock, there are limited studies on the dermatopathological aspects of natural tick infestation in cattle. This study aimed to describe the gross and histologic aspects of cutaneous lesions caused by tick infestation in cattle. Thirteen cases were selected based on necropsy data from a 10-year retrospective study. Predispositions were observed in beef cattle (P = .049) and the Angus breed (P = .012), and lesions occurred mainly in the fall (P = .007). Gross lesions included hypotrichosis (13/13; 100%), scales (12/13; 92%), alopecia (11/13; 85%), ulcers (7/13; 54%), crusts (7/13; 54%), and erosions (2/13; 15%). These gross lesions were mainly located in the thorax (12/13; 92%), head (11/13; 85%), abdomen (10/13; 77%), neck (9/13; 69%), limbs (9/13; 69%), and perineum (9/13; 69%). Histologically, all cases had ticks adhered to the epidermis with erosions (13/13; 100%), ulcers (11/13; 85%), orthokeratotic hyperkeratosis (13/13; 100%), irregular acanthosis (13/13; 100%), intraepidermal pustules (13/13; 100%), crusts (10/13; 77%), and ballooning degeneration (4/13; 31%). In the dermis, just below the tick insertion site, there was coagulation necrosis, fibrin deposition, and inflammatory infiltrate composed of mixed cells (neutrophils, lymphocytes, plasma cells, macrophages, and few eosinophils) (9/13; 69%), neutrophils (3/13; 23%), or eosinophils (1/13; 8%). This study reinforces the different patterns of cutaneous lesions caused by tick infestation in cattle, which should be considered as a potential cause of dermatitis in this species.

Brazilian porcupinepox virus infection in a free-ranging neotropical porcupine in Mato Grosso, Brazil.

Although the novel Brazilian porcupinepox virus (BPoPV) can infect wild porcupines, its lethality and zoonotic potential are not well-established. In May 2021, a free-ranging neotropical porcupine (Coendou longicaudatus boliviensis) rescued from the natural savanna in the Brazilian Cerrado, Mato Grosso State, was presented with a lethal poxviral infection. Clinical signs and PCR detection of BPoPV supported the diagnosis. Poxviral lesions included erythema, exfoliative dermatitis, and erosions involving mainly the face, hindlimb, and vulva. Histologically, the lesions consisted of proliferative and necrotic dermatitis, intraepidermal and follicular pustules, and intracytoplasmic inclusion bodies in keratinocytes. Phylogenetic analysis revealed BPoPV strains closely related to other rodent-infecting poxviruses. This poxviral infection resulted in the death of a specimen of C. l. boliviensis; the effect on species conservation, and the potential of spillover into humans and other vertebrates remain unknown.

Sores of boreal moose reveal a previously unknown genetic lineage of parasitic nematode within the genus Onchocerca.

Long-standing reports of open sores on the hind legs of moose (Alces alces) have been recorded in Alaska (as well as Canada, Europe, and Michigan), eliciting concerns about causes and infection. We used histological and genomic methods to investigate the sores from 20 adult moose on the Kenai Peninsula, Alaska. We paired this with thermal imagery and molt scoring of adult moose to further describe sore formation and understand its timing. Severe, ulcerative and eosinophilic dermatitis was found in all moose with sores present, and microfilariae within intraepidermal pustules were additionally found in four samples. Genetic analysis of sores from moose revealed a previously unknown genetic lineage of Onchocerca. Adult moose molt and lose their barrier of protection against flies in June and July during peak fly activity, leaving them vulnerable and allowing the development of sores. In summary, our results indicate that the cause for the sores on the hindleg of moose is a previously unknown genetic lineage of Onchocerca, probably transmitted by black flies, in timing with the molt cycle of adult moose. These sores leave moose exposed to pathogens, making them vulnerable, and challenging their health and fitness.

Clinical Manifestations and Management of Terbinafine‐Induced Acute Generalized Exanthematous Pustulosis

Background. Acute generalized exanthematous pustulosis (AGEP) is a rare and serious adverse reaction of terbinafine. Understanding AGEP and terbinafine is primarily based on case reports. The purpose is to explore the clinical characteristics of terbinafine‐induced AGEP, and to provide reference for clinical diagnosis and treatment. Methods. Case reports and original studies of terbinafine‐induced AGEP were retrieved by searching Chinese and English databases from January, 1991, to May 31, 2022. Results. The median age of the 32 patients (17 males and 15 females) was 55 years (range: 6–84). The median time to onset of AGEP is 8 days (range: 1–77) and is usually accompanied by fever (&gt;38°C) and elevated neutrophil levels (&gt;8000/mm3). Four patients (12.5%) had oral mucosal involvement, and 10 patients (31.3%) developed postpustular desquamation. The lesions were mainly distributed in the trunk (43.8%), the whole body (34.4%), and the extremities (53.1%). Skin biopsy revealed subcorneal pustules (65.6%), intraepidermal cavernous pustules (43.8%), necrotic keratinocytes (15.6%), spongy hyperplasia (25.0%), neutrophil exocytosis (34.4%), and papillary dermal edema (40.6%). AGEP resolved completely in all patients at a median time of 12 days (range: 2–90) after discontinuation of terbinafine and symptomatic therapy. Conclusion. Clinicians should be aware that terbinafine‐induced AGEP is a rare cutaneous adverse reaction. AGEP usually occurs within 2 weeks after administration and has a good prognosis after discontinuation.

Suspected human intravenous immunoglobulin‐induced acute haemolytic anaemia in a dog

A 2-year-old mixed breed dog presented with a 1-year history of crust and erosion on the nasal planum. Because histopathological examination revealed ruptured intraepidermal pustules and superficial dermal inflammation, the dog was diagnosed with pemphigus foliaceus. Human intravenous immunoglobulin was administered in two consecutive doses of 0.5g/kg/day due to poor therapeutic response to previous immunosuppressive therapy. From Day 3 after the first dose of human intravenous immunoglobulin, tachypnoea, pale mucous membrane, haemoglobinuria and haemoglobinemia were observed, thus confirming haemolytic anaemia. Other drug-induced haemolytic anaemias were excluded because no additional drugs had been administered before the haemolysis occurred. Immune-mediated haemolytic anaemia was also excluded because the direct antiglobulin test was negative. Two transfusions were performed, and haemolysis was not observed from Day 4 of haemolytic anaemia onset. In conclusion, human intravenous immunoglobulin-induced haemolytic anaemia should be considered in dogs that develop haemolysis following the administration of human intravenous immunoglobulin.

Dietary habits in Japanese patients with palmoplantar pustulosis.

Palmoplantar pustulosis (PPP) is a chronic dermatitis characterized by sterile intra-epidermal pustules associated with erythema and scales on the palms and soles. Tumor necrosis factor (TNF)-α/interleukin (IL)-23/IL-17 inflammatory pathway may be involved in the pathogenesis of PPP, and the skin lesions manifest the enhanced expression of IL-8 in keratinocytes and increased levels of antimicrobial peptide cathelicidin, leucine leucine-37 in vesicles/pustules. Some PPP patients are associated with arthro-osteitis, called pustulotic arthro-osteitis (PAO). Dietary habits may modulate the pathogenesis of PPP, however, have not been investigated in PPP patients. We evaluated dietary habits in adult Japanese PPP patients, using a validated, brief-type self-administered diet history questionnaire, and compared their results to those of age- and sex-matched healthy controls. The results in PPP patients with PAO were compared to those in the patients without. Japanese PPP patients showed higher body mass indices (BMIs), higher intakes of pulses and sugar/sweeteners, and lower intake of vitamin A, compared to those of healthy controls. The bivariate and multivariable logistic regression analysis showed that PPP was associated with high BMI, high intake of pulses, and low intake of vitamin A. The sodium intake and BMI were positively correlated with palmoplantar pustulosis area and severity index (PPPASI). The linear multivariate regression analysis revealed that sodium intake and BMI were predictors of PPPASI. The age and sodium intake in the patients with PAO were lower than those in the patients without. The bivariate and multivariable logistic regression analysis showed that PAO was negatively associated with age and sodium intake. This is the first study showing the dietary habits in patients with PPP. Further studies should clarify if the dietary intervention to correct the BMI and sodium intake will alter the progress of PPP.

A retrospective study on the clinicopathologic features of IgG/IgA pemphigus

A retrospective study on the clinicopathologic features of IgG/IgA pemphigus

Iohexol-Induced Acute Generalized Exanthematous Pustulosis (AGEP): Case Report

Acute generalized exanthematous pustulosis (AGEP) is a rare adverse drug reaction characterized by numerous non-follicular sterile pustules overlying edematous, erythematous plaques. The majority of AGEP cases are associated with antimicrobial medications, although other agents and etiologies have also been implicated. Here, we report a patient with recurrent angioimmunoblastic T-cell lymphoma (AITL) who presented with a pruritic and widespread pustular eruption one week following computed tomography (CT) with iohexol contrast administration. Notably, she had a documented prior mild reaction to contrast medium and was appropriately pre-medicated with diphenhydramine and prednisone before imaging. Biopsy revealed intra-epidermal pustules, epidermal spongiosis, and dermal infiltrate of lymphocytes, neutrophils, and some eosinophils – histological findings consistent with AGEP. Systemic and topical corticosteroids plus topical mupirocin resulted in complete resolution of symptoms. While cutaneous reactions to iodinated contrast are common and often self-limited, severe manifestations such as AGEP must be considered particularly in patients with a history of prior contrast allergy.

Molecular detection of fungal and bacterial DNA from pustules in patients with palmoplantar pustulosis: special focus on Malassezia species.

Palmoplantar pustulosis (PPP) is a distinct, chronic skin disorder characterized by intraepidermal pustules on the palms and soles. It is hypothesized that microorganisms on the skin might induce the symptoms of PPP via inflammatory cell activation. However, the microbiota has not been studied in detail because of the assumption that the pustules in PPP are sterile. To elucidate the role of microorganisms in pathogenesis of PPP. PCR analysis was performed of microbial DNA fragments in the pustules of patients with PPP. The sequence of the D1/D2 LSU 26s rRNA gene and that of the 16S rRNA gene was used for fungal and bacterial DNA detection, respectively. In total, 71 samples were carefully collected from the pustules of patients with PPP. Fungal DNA bands were detected in 68 samples, and fungi including Malassezia spp. were identified in 30 of 71 samples (42.3%). Malassezia restricta was the most frequently encountered fungus (14/71; 19.7%). However, bacterial DNA was not detected by the methods used. Furthermore, identical fungal DNA was not detected in the outer lid of the pustules, suggesting that the fungi detected within the pustule did not derive from contamination via the skin surface. In the present study, we demonstrated for the first time that certain pustules in patients with PPP contain fungal DNA fragments, especially those of Malassezia spp. Our findings provide new insights on the role of skin microbiota in the pathogenesis of PPP.

Distinguishing pustular psoriasis and acute generalized exanthematous pustulosis on the basis of plasmacytoid dendritic cells and MxA protein.

Distinguishing acute generalized exanthematous pustulosis (AGEP) and pustular psoriasis (PS) can be challenging. Staining for plasmacytoid dendritic cells, or PDCs (producer of IFN-α/β), and MxA (an IFN-α/β inducible protein) may help discriminate these entities. Forty-three cases of AGEP and PS were compiled from two academic institutions. All cases were examined for CD123+ PDCs, eosinophils, acanthosis, papillomatosis, suprapapillary plate thinning, tortuous dilated capillaries, single necrotic keratinocytes, papillary dermal edema, vasculitis, eosinophil exocytosis, intraepidermal pustules, and subcorneal pustules. A subset of cases (n = 26) was stained for MxA. Perivascular and intraepidermal PDCs, dilated tortuous vessels, and MxA expression in the dermal inflammatory infiltrate were significantly (P < 0.05) in favor of a diagnosis of PS. The absence of PDCs and presence of eosinophils favored a diagnosis of AGEP (P < 0.05). We found compelling evidence for the use of CD123 to highlight PDCs in these cases. The presence of PDCs and expression of MxA in dermal inflammatory infiltrate, as well as absence of eosinophils and presence of tortuous dilated capillaries favored a diagnosis of PS. Expression of MxA in the dermal infiltrate corresponds with a Th1 pathway in PS and may indicate a Th1 component in the early initial phase of AGEP.

ACUTE GENERALIZED EXANTHEMATOUS PUSTULOSIS PRESENTING AS DISTRIBUTIVE SHOCK WITH MULTI-ORGAN FAILURE

SESSION TITLE: Critical Care 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Acute Generalized Exanthematous Pustulosis (AGEP), or Pustular Drug Eruption, is a rare cutaneous condition most commonly induced by drug or toxin exposure. AGEP is manifested pathologically by acute sterile intraepidermal pustular eruptions and is a rare presentation of febrile drug reaction. Prior cases have described this pathology as similar in presentation to septic shock or toxic epidermal necrolysis. Vancomycin, antiepileptic agents, non-steroidal anti-inflammatory medications, antibiotics, and diltiazem have all been identified as possible etiologies of AGEP. Here we present a rare case of AGEP in a patient with no prior medication exposures presenting with shock and multisystem organ failure. CASE PRESENTATION: An 86 year-old woman presented to the Emergency Department (ED) with report of recurrent high grade fevers and progressive maculopapular rash for one week. The patient had previously been evaluated by outpatient dermatology. Biopsy was performed and results were pending at the time of initial ED evaluation. Symptoms were additionally refractory to topical steroid therapy. ED course was significant for tachycardia (110 beats per minute), hypotension (84/48 mmHg), fever (103˚F), bandemia (15%) and acute kidney injury (AKI). The patient was admitted to the Intensive Care Unit with distributive shock of unclear etiology. The patient received intravenous fluid resuscitation, norepinephrine infusion, vancomycin, and piperacillin/tazobactam. She subsequently developed multiorgan failure involving the renal, hepatic, cardiac and respiratory systems. Prior skin biopsy results were obtained and revealed intraepidermal neutrophilic pustules with no evidence of infection. Findings were consistent with AGEP. An extensive evaluation for an infectious etiology was unremarkable. Antibiotic therapy was discontinued and the patient was treated with pulse methylprednisolone therapy with a prolonged prednisone taper. The patient improved on steroid therapy and resolution of multiorgan failure was noted. The patient was subsequently discharged to a rehabilitation facility. DISCUSSION: AGEP is a rare cutaneous condition typically associated with medication or toxin exposure. We present a unique case of idiopathic AGEP in a patient with no prior infectious, toxic or medication exposures. This case is likewise unique with respect to disease severity and only four prior case reports describe AGEP progressing to multiorgan failure and shock. CONCLUSIONS: This is the first case, to our knowledge, describing the use of pulse dose steroids in the treatment of severe AGEP. Pulse therapy, in this setting, led to complete resolution of multiorgan dysfunction. Determination of the etiology of distributive shock is essential for the prompt and appropriate treatment of patients in the critical care setting. Reference #1: Mohyuddin GR, Al Asad M, Scratchko L, Khaleeq G. Acute generalized exanthematous pustulosis with multiple organ dysfunction syndrome. Am J Crit Care. 2013;22(3):270-3. Reference #2: Lesterhuis WJ, Tjioe M, Stumpenhausen GA, van Crevel R. Acute generalized exanthematous pustulosis mimicking septic shock. Am J Med. 2004;116(8):574-5. Reference #3: Shim K, Choi Y, Lee S, Lee H, Choi G, Kim H, Suh K. A case of acute generalized exanthematous pustulosis with patterns of septic shock. Korean J Med. 2011; 81(6):802-806. DISCLOSURES: No relevant relationships by George Elkomos-Botros, source=Web Response No relevant relationships by Mina Makaryus, source=Web Response No relevant relationships by Nirvi Shah, source=Web Response

Acute generalized exanthematous pustulosis caused by lincomycin: a case report

A 28-year-old male patient with coughing was treated with intramuscular injection of lincomycin, oral Kesouting granules and erythromycin in a local clinic. One day later, erythema occurred on the head and face, and rapidly spread to the trunk and limbs. Three days later, a large number of densely distributed needle tip- to millet-sized pustules occurred on the generalized erythema all over the body with fever and burning pain sensation of the skin. Skin examination revealed diffuse edematous erythema with obvious hyperemia on more than 90% of the body, a large number of needle tip- to millet-sized white-yellowish pustules on the erythema on the hair line, face, flexor aspect of the extremities and flexural site of the trunk (axillary and inguinal regions) , and bilateral lower-extremity swelling. No erythema or erosion was observed on the oral mucosa or genital mucosa. Histopathological examination of skin lesions on the right elbow showed local intraepidermal and subcorneal pustules, necrotic keratinocytes and neutrophil aggregation in the pustules, and infiltration of lymphocytes and eosinophils in the superficial dermis. Laboratory examination showed elevated white blood cell counts (26.9 × 109/L) , neutrophils proportion (Segment, 0.88) , C-reactive protein level (127.89 mg/L) , aspartate aminotransferase level (44.2 U/L) and alanine transarninase level (77.3 U/L) , but decreased proportion of lymphocytes (0.08) . The patient was diagnosed with acute generalized exanthematous pustulosis. After admission, the patient was treated with intravenous drips of methylprednisolone at a dose of 60 mg/d. Then, the condition was rapidly relieved, and the dosage was rapidly reduced. The patient was discharged on day 7. Key words: Acute generalized exanthematous pustulosis; Lincomycin; Drug eruptions; Drug-induced liver injury

Clinical and Immunological Study of 30 Cases With Both IgG and IgA Anti-Keratinocyte Cell Surface Autoantibodies Toward the Definition of Intercellular IgG/IgA Dermatosis.

Several sporadic cases, in which direct and indirect immunofluorescence studies simultaneously detected IgG and IgA autoantibodies to keratinocyte cell surfaces, have been reported mainly under the name of IgG/IgA pemphigus. However, there have been no systematic studies for this condition. In this study, we collected 30 cases of this condition from our cohort of more than 5,000 autoimmune bullous disease cases, which were consulted for our diagnostic methods from other institutes, and summarized their clinical and immunological findings. Clinically, there was no male–female prevalence, mean age of disease onset was 55.6 years, and mean duration before this condition was suspected was 18 months. The patients showed clinically bullous and pustular skin lesions preferentially on the trunk and extremities, and histopathologically intraepidermal pustules and blisters with infiltration of neutrophils and eosinophils. Immunologically, ELISAs frequently detected IgG and IgA autoantibodies to both desmogleins and desmocollins. From the characteristic clinical, histopathological, and immunological features, which are considerably different from those in classical IgG types of pemphigus, we propose this disease as a new disease entity with preferential name of intercellular IgG/IgA dermatosis (IGAD). This was the largest study of IGAD to date.

Acute Generalised Exanthematous Pustulosis: An Update.

Acute generalised exanthematous pustulosis (AGEP) is a severe cutaneous adverse reaction and is attributed to drugs in more than 90% of cases. It is a rare disease, with an estimated incidence of 1–5 patients per million per year. The clinical manifestations characterised by the rapid development of sterile pustular lesions, fever and leucocytosis. Number of drugs has been reported to be associated with AGEP, most common being the antibiotics. Histopathologically there is intraepidermal pustules and papillary dermal oedema with neutrophilic and eosinophilic infiltrations. Systemic involvement can be present in more severe cases. Early diagnosis with withdrawal of the causative drug is the most important step in the management. Treatment includes supportive care, prevention of antibiotics and use of a potent topical steroid.

Anti-tumor necrosis factor-induced palmoplantar psoriasis: Case series

Palmoplantar pustular psoriasis (PPP) is a very uncommon form of psoriasis. Patients usually present with sterile, intraepidermal pustules over palms and soles, and it is difficult to treat. Women and smokers may be at a higher risk of getting PPP. Here, we report 2 patients who developed new PPP lesions after initiation of adalimumab (Humira®). Case reports are for a 19-year-old female diagnosed with Crohn's disease on February 2012 after a long history of abdominal pain and bleeding and a 34-year-old female who had psoriatic arthritis with no skin lesions since November 2012. Our recommendation is for the patients to be controlled with potent topical corticosteroids, keratolytics, Vitamin D analogs, phototherapy, increases in baseline methotrexate doses, and cyclosporine as needed.

An elderly Filipino woman with follicular papules of the face and chest

An elderly woman developed pruritic follicularpapules over a period of 5 years. A biopsy revealedfocal intraepidermal eosinophilic pustules, leading tothe diagnosis of Ofuji disease or eosinophilic pustularfolliculitis. A discussion of this condition is presented.

Staphylococcus aureus penetrate the interkeratinocyte spaces created by skin-infiltrating neutrophils in a mouse model of impetigo.

Impetigo is a bacterial skin disease characterized by intraepidermal neutrophilic pustules. Previous studies have demonstrated that exfoliative toxin producing staphylococci are isolated in the cutaneous lesions of human and canine impetigo. However, the mechanisms of intraepidermal splitting in impetigo remain poorly understood. To determine how staphylococci penetrate the living epidermis and create intraepidermal pustules invivo using a mouse model of impetigo. Three Staphylococcus aureus strains harbouring the etb gene and three et gene negative strains were epicutaneously inoculated onto tape-stripped mouse skin. The skin samples were subjected to time course histopathological and immunofluorescence analyses to detect intraepidermal neutrophils and infiltrating staphylococci. To determine the role of neutrophils on intraepidermal bacterial invasion, cyclophosphamide (CPA) was injected intraperitoneally into the mice to cause leucopenia before the inoculation of etb gene positive strains. In mice inoculated with etb gene positive S.aureus, intraepidermal pustules resembling impetigo were detected as early as 4h post-inoculation (hpi). Neutrophils in the epidermis were detected from 4hpi, whereas intraepidermal staphylococci was detected from 6hpi. The dimensions of the intraepidermal clefts created in mice inoculated with etb gene positive strains at 6hpi were significantly larger than those in mice inoculated with et gene negative strains. In CPA treated mice, staphylococci or neutrophils were not detected in the deep epidermis until 6hpi. Our findings indicate that intraepidermal neutrophils play an important role in S.aureus invasion into the living epidermis in a mouse model of impetigo.

Clinical and immunological studies of 49 cases of various types of intercellular IgA dermatosis and 13 cases of classical subcorneal pustular dermatosis examined at Kurume University.

Intercellular IgA dermatosis (IAD) is a subset of autoimmune bullous disease exclusively with IgA antikeratinocyte cell-surface antibodies. The classification and pathogenesis of this condition are still obscure. To classify IAD and study its pathogenesis. From our cohort of 5402 cases of autoimmune bullous disease, we selected 49 cases of various types of intercellular IgA dermatosis (IAD) and 13 cases of classical subcorneal pustular dermatosis (SPD), for which sera and information were available. We studied these cases clinically and immunologically. There were 17 SPD-type IAD, 12 intraepidermal neutrophilic IgA dermatosis (IEN)-type IAD, two IgA-pemphigus vegetans, four IgA-pemphigus foliaceus, six IgA-pemphigus vulgaris and eight unclassified IAD cases. There was no sex predominance, and the average age at disease onset was 45·9years. Clinically, bullous and pustular skin lesions developed on various sites, particularly intertriginous areas. Histopathology showed intraepidermal blisters or pustules at the upper epidermis in the SPD-type and at the midepidermis in the IEN-type. Immunological studies revealed that direct immunofluorescence, indirect immunofluorescence of normal human skin and enzyme-linked immunosorbent assays (ELISAs) of recombinant proteins of desmogleins and desmocollins frequently showed positive results, although no antigens were detected in many cases. All cases of classical SPD, which showed no positive immunological results, were indistinguishable clinically and histopathologically from SPD-type IAD. The present study of the largest cohort of cases of IAD showed that themajor subtypes are SPD and IEN, and that the combination of indirect immunofluorescence and ELISAs of desmogleins and desmocollins, in addition to direct immunofluorescence, was useful for the diagnosis of IAD and its subtypes.