Serum IgE reactivity to Malassezia furfur extract and recombinant M. furfur allergens in patients with atopic dermatitis

IgE reactivity to the opportunistic yeast Malassezia furfur can be found in patients with atopic dermatitis (AD). We have previously cloned and expressed 6 recombinant allergens (rMal f 1, rMal f 5-9) from M. furfur. In the present study, we used ImmunoCAP to investigate whether these rMal f allergens can be useful in the diagnosis of M. furfur-associated AD compared with the M. furfur extract. A total of 156 adult patients with a clinical diagnosis of AD participated in the study. Sixty-four percent had increased total serum IgE levels, 79% had specific IgE antibodies to common inhalant allergens and 47% had IgE antibodies to M. furfur extract. IgE antibodies to any of the rMal f allergens were detected among 86 (55%) of the patients, 14 (16%) of whom did not react to the M. furfur extract. Any individual rMal f allergen detected between 32% and 89% of the patients ImmunoCAP-positive to the M. furfur extract, with the highest sensitivity for rMal f 9. Therefore, a couple of individual rMal f allergens can improve the diagnosis of M. furfur-associated IgE allergies in patients with AD.     

Positive atopy patch test reaction to Malassezia furfur in atopic dermatitis correlates with a T helper 2-like peripheral blood mononuclear cells response

The yeast Malassezia furfur belongs to the normal cutaneous flora, but is also a triggering allergen that can contribute to atopic dermatitis. To illuminate the effect of circulating allergen-specific T cells in atopic dermatitis, the peripheral mononuclear cell response was correlated with the in vivo skin prick test and atopy patch test reactivity to M. furfur. None of 16 healthy controls showed any positive in vivo reaction. The 40 atopic dermatitis patients, of whom 18 had serum IgE reactivity to M. furfur, were subdivided according to their in vivo reaction to M. furfur extract into three groups: skin prick test positive/atopy patch test positive (n = 12), skin prick test positive/atopy patch test negative (n = 12), and skin prick test negative/atopy patch test negative (n = 16). The skin prick test positive/atopy patch test positive and the skin prick test positive/atopy patch test negative groups had a significantly higher peripheral mononuclear cell stimulation index than the healthy controls. Interestingly, the stimulation index values in the skin prick test positive/atopy patch test positive group were significantly higher than in the skin prick test positive/atopy patch test negative group. In the M. furfur skin prick test positive atopic dermatitis patients (n = 24) a correlation was found between stimulation index and the M. furfur atopy patch test reactions, but not between stimulation index and M. furfur-specific serum IgE levels. Skin prick test positive and/or atopy patch test positive reactions to the recombinant M. furfur allergens rMal f 1, rMal f 5, and rMal f 6 were observed in 7, 14, and 16 of the 40 atopic dermatitis patients, respectively. Further, there was a correlation between production of the T helper 2-related cytokines interleukins 4, 5, and 13 and stimulation index to M. furfur extract, but not between the T helper 1-related interferon-gamma and stimulation index to M. furfur extract. Our data strongly suggest a relationship between circulating specific T cells with a T helper 2-like cytokine profile and positive atopy patch test reactions.     

IgE antibodies to Malassezia furfur, M. sympodialis and Pityrosporum orbiculare in patients with atopic dermatitis, seborrheic eczema or pityriasis versicolor, and identification of respective allergens

Malassezia yeasts may be a trigger factor for atopic dermatitis. Following the recent reclassification of the genus, the presence of specific IgE antibodies was examined in the sera of patients with atopic dermatitis (n = 223), pityriasis versicolor (n = 83), seborrheic eczema (n = 50) and hymenoptera allergy (n = 39) and in controls without skin diseases (n = 50). In addition to using the commercially available radioallergosorbent test (RAST) for Pityrosporum orbiculare couplings were also made against the reference strains for M. furfur and M. sympodialis. To characterize the specificity and molecular weight of corresponding epitopes identical material was used for production of an immunoblot. Despite high total levels of IgE, controls and patients with pityriasis versicolor showed no specific IgE antibodies. Six patients (12%) with seborrheic eczema were positive while 78 patients (35%) with atopic dermatitis had specific IgE antibodies in higher RAST classes that differed between the Malassezia species. The molecular weights of the main antigens of M. sympodialis and M. furfur were determined to be 15, 22, 30, 37, 40, 58, 79, 92, 99 and 124 kDa and 15, 25, 27, 43, 58, 92, 99 and 107 kDa, respectively. Evaluated according to the location of their disease, patients with head and neck lesions most frequently showed Malassezia-specific IgE antibodies. However, there were differences between the Malassezia species tested, the previously used strain P. orbiculare being assignable to the species M. sympodialis.     

Antigenic components of Malassezia species for immunoglobulin E antibodies in sera of patients with atopic dermatitis

Antigenic components of Malassezia furfur, M. globosa, M. restricta, M. slooffiae, and M. sympodialis were studied for immunoglobulin E antibodies in sera of patients with atopic dermatitis (AD). Antigenic components were extracted from Malassezia cells by treatment with beta-mercaptoethanol, referred to as 2-ME extract. CBB staining and lectin blots using Con A, LCA, PHA-E4, PNA or RCA120 showed that the 2-ME extracts contained several species-dependent components that differed quantitatively and qualitatively among the Malassezia species at the protein level. In the Western blot with the 2-ME extracts, of 54 sera of the patients with AD (54 patients), the patients' IgE antibodies most frequently recognized components showing molecular weights of 43-46 kDa for M. slooffiae, 12-22 kDa for M. sympodialis, 35-40 kDa for M. restricta, 45-50 kDa for M. globosa, and of 67-72 kDa for M. furfur, respectively. In the correlative study, in which the total band intensities generated for each extract in Western blot were compared among the Malassezia species, the intensity for M. globosa was well correlated with that for M. sympodialis (r=0.756). In the Western blot inhibition test, the 2-ME extract of M. globosa partially inhibited the reaction of the antigenic components of other Malassezia species with the patient's IgE antibodies. These results indicated that Malassezia species contained both species-specific and common antigenic components at the IgE antibody level.     

The prevalence of Malassezia yeasts in patients with atopic dermatitis, seborrhoeic dermatitis and healthy controls

Cultures for Malassezia yeasts were taken from both normal-looking skin and lesional skin in 124 patients with atopic dermatitis, 16 patients with seborrhoeic dermatitis and from normal skin of 31 healthy controls. Positive Malassezia growth was found in fewer patients with atopic dermatitis (56%) than in patients with seborrhoeic dermatitis (88%) or in healthy controls (84%, p<0.01). In the patients with atopic dermatitis, fewer positive cultures were found in lesional (28%) than in non-lesional skin (44%, p<0.05), while positive cultures were found in 75% of both lesional and non-lesional skin of patients with seborrhoeic dermatitis (not significant). M. sympodialis dominated in patients with atopic dermatitis (46%) and in healthy controls (69%). In patients with seborrhoeic dermatitis both M. sympodialis and M. obtusa were cultured in 43%. A Malassezia species extract mixture would increase the possibility of detecting IgE sensitization to Malassezia in patients with atopic dermatitis.     

Results of atopy patch tests with house dust mites in adults with ''intrinsic'' and ''extrinsic'' atopic dermatitis

BACKGROUND: The most frequently employed diagnostic criteria of atopic dermatitis (AD) can be fulfilled in the absence of elevated total circulating IgE or specific IgE to food allergens or environmental aeroallergens and/or in the absence of personal or familial history of atopy as well. Therefore a distinction between 'extrinsic' or 'allergic' and 'intrinsic' or 'non-allergic' AD has been suggested. Recently, a patch test with environmental aeroallergens, named atopy patch test (APT), has been proposed for use in the study of AD. OBJECTIVE The aim of this study was to investigate the reactivity to APT in patients with 'extrinsic' and 'intrinsic' AD. PATIENTS, MATERIALS AND METHODS: Two groups of adult male subjects with AD were examined consecutively in our department (Department of Dermatology, Italian Navy Main Hospital, Taranto, Italy) andpatch tested with whole bodies of house dust mites (HDM) at a concentration of 20% in petrolatum (Dermatophagoides pteronyssinus 50%, D. farinae 50%). The groups included: (i) 95 patients affected by the adult clinical form of 'extrinsic' AD; (ii) 12 patients affected by the adult clinical form of 'intrinsic' AD; and (iii) a control group of 49 adult healthy male subjects with a negative anamnesis for eczema and atopy and negative skin prick test to aeroallergens/food allergens and/or normal level of total circulating IgE, also patch tested with the same allergen. The statistical differences were calculated by chi2 test and 95% confidence intervals (CI) were provided. RESULTS: The APT was positive in 47.4% (CI: 37-57%) of'extrinsic'AD, in 66.6% (CI: 41-93%) of'intrinsic' AD and in 12.2% (CI: 3-21%) of healthy subjects. The differences between the two AD subgroups and the control group were statistically significant (P < 0.001). CONCLUSIONS: APT positivity is more frequent in both 'extrinsic' and 'intrinsic' AD than in unaffected subjects. Other studies are needed to confirm our data and to explain why the APT is positive in the 'intrinsic' form.     

Sensitization to the yeast Malassezia sympodialis is specific for extrinsic and intrinsic atopic eczema

The opportunistic yeast Malassezia sympodialis belongs to the normal cutaneous flora but can also cause IgE-mediated sensitization in patients suffering from atopic eczema (AE). We investigated 706 individuals by ImmunoCAPm70 and skin-prick tests with a crude M. sympodialis extract. In AE patients, we further performed skin prick tests, atopy patch tests, ELISA, and peripheral blood mononuclear cells proliferation assays with recombinant M. sympodialis allergens (rMala s 1 and 5-9). In 52/97 patients with AE-specific IgE against M. sympodialis was detectable. Almost no reactivity to M. sympodialis was seen in patients suffering from other allergic diseases (4/571) and no reactivity at all was seen in healthy controls (0/38). Skin tests showed variable recognition patterns against the different molecular structures with a predominant sensitization to rMala s 1, 5, 6, and 9, confirmed also by specific serum IgE to these allergens. Interestingly, IgE- and T-cell-mediated reactivity against M. sympodialis was also found in patients with the intrinsic form of AE. Thus, sensitization to M. sympodialis is specific for AE patients and occurs in both the extrinsic and intrinsic variant of eczema. Recombinant yeast allergens represent a useful tool to study molecular structures and differential sensitization patterns in the pathogenesis of AE.     

Cutaneous hypersensitivity to Malassezia sympodialis and dust mite in adult atopic dermatitis with a textile pattern

Atopic dermatitis (AD) patients with predominantly head and neck involvement react to patch tests of the yeast Malassezia sympodialis (Ms). Protein patch testing methods and interpretation are controversial, but subgroups of AD patients may have unique triggers for disease activity. The aim of the study was to identify clinical characteristics of patients who are patch test-positive to Dermatophagoides farinae/pteronyssinus (Df) and Ms and characterize cutaneous cytokine profiles of the atopy patch tests (APTs). 25 AD patients and 27 control dermatitis patients were patch tested with Ms and Df. Qualitative analysis of Th-1 and Th-2 cytokines by RT-PCR mRNA was obtained from positive APTs. Atopic dermatitis patients with a textile pattern or head and neck involvement demonstrated more positive APTs to Ms than control patients. Early positive APTs (<6 hr) did not exhibit a Th-1 type cytokine profile. The subgroup of adult AD patients with head, neck and upper torso pattern of dermatitis seems most likely to react to Ms (and Df). The immune mechanism of protein patch tests includes a Th-1 cell-mediated component after 6 hr or more.     

Cutaneous Malassezia flora in atopic dermatitis differs between adults and children

BACKGROUND: Malassezia species are suspected to be involved in the development of skin lesions in atopic dermatitis (AD) when the response of adult AD to anti-inflammatory treatments is poor. However, a comparative analysis of Malassezia flora between adults and children with AD has not been performed. OBJECTIVES: To compare the cutaneous Malassezia flora between adults and children with AD. METHODS: Scale samples were collected from skin lesions of 58 patients with AD in the head and neck regions (28 males and 30 females; 31 children and 27 adults), and fungal DNA was extracted from the samples directly. The number and identities of the Malassezia species were analysed with high accuracy using a polymerase chain reaction-based culture-independent method. The in vivo level of anti-Malassezia IgE antibody was also assayed. RESULTS: Malassezia restricta was the predominant species in the children with AD, while both M. restricta and M. globosa predominated in the adults. The adults showed increased sensitization in terms of anti-Malassezia-specific IgE responses in the sera to both M. globosa and M. restricta in comparison with the children. CONCLUSIONS: The cutaneous Malassezia flora differs significantly between the two age groups.     

Malassezia sympodialis stimulation differently affects gene expression in dendritic cells from atopic dermatitis patients and healthy individuals

It is known that 28-84% of patients with atopic dermatitis exhibit IgE and/or T-cell reactivity to the opportunistic yeast Malassezia sympodialis, which can be taken up by immature monocyte-derived dendritic cells (MDDCs), resulting in MDDC maturation. The aim of this study was to investigate whether MDDCs from patients with atopic dermatitis respond differently to M. sympodialis compared to MDDCs from healthy individuals. Immature MDDCs were stimulated with M. sympodialis and the gene expression profiles were analysed with cDNA arrays containing 406 genes. Our results show that M. sympodialis differently affected MDDCs from patients with atopic dermatitis, and more so in severely ill patients, compared with healthy individuals. Six genes were more than fivefold up-regulated in MDDCs from more than one patient with atopic dermatitis, coding for CD54, CD83, IL-8, monocyte-derived chemokine (MDC), BTG1 and IL-1R antagonist. In healthy individuals this was true only for BTG1. Up-regulations of IL-8 and MDC were confirmed at the protein level. Our findings might reflect an increased trafficking and stimulatory capacity in MDDCs from the patients, which is likely to result in a stronger inflammatory response to M. sympodialis.     

Head and neck dermatitis: the role of Malassezia furfur, topical steroid use and environmental factors in its causation

The aetiology of head and neck dermatitis (HND), one subgroup of postpubertal atopic dermatitis (AD), is still unclear. The aim of this study was to evaluate the influence on HND of common environmental factors, long-term topical steroid use, and the role of Malassezia furfur infection. Relevant information was obtained from 100 patients with HND attending our dermatology clinic by means of both physical examinations and questionnaires. Corticosteroid-induced vasoconstriction was estimated by visual scoring of laser-Doppler flowmetry. and the following immunological studies were performed: skin prick test, measurement of total IgE, eosinophil cationic protein, and specific IgE antibodies to several fungal antigens including those of M. furfur. The questionnaire revealed that sweating (81%), heat (71%), dryness (70%), psychic stress (67%), and sun exposure (50%) were responsible for aggravation of skin lesions. The vascular response to topical steroid was reduced in HND patients as compared with that of normal healthy controls (P < 0.05). Fifty-four of 80 patients with HND (68%) had anti M. furfur-specific IgE antibodies and 36 of 80 patients (45%) showed positive skin prick tests for M. furfur. The clinical severity and serum total IgE of HND patients were higher in patients with positive response to anti-M. furfur-specific IgE antibodies than in patients with negative response (P < 0.05). These results suggest that HND can be aggravated not only by M. furfur but also by environmental factors such as sweating, heat, dryness, psychic stress and sun exposure. Furthermore, long-term use of topical steroid might be associated with the development of diffuse erythematous lesions with telangiectasia on the head and neck areas.     

Atopic disease and serum immunoglobulin-E

Fifty-seven subjects, forty-three with various combinations of atopic disease and fourteen non-atopic controls, were studied using a battery of immediate skin test allergens and a radio-immunoassay for serum Immunoglobulin-E (IgE). The geometric mean serum IgE level (units/ml) was 50 in strictly nonatopic controls, 170 in atopic respiratory disease (ARD) patients, 320 in atopic dermatitis (AD) patients and 772 in those patients with both AD-ARD. The marked elevation of the serum IgE in the latter group was not associated with respiratory disease activity and not closely correlated with extent of the dermatitis, but may relate to patients with both AD-ARD being 'highly atopic'. Overall, there was no correlation between the serum IgE level and the frequency of positive skin tests. Compared to ARD patients, the serum of AD patients contained more IgE, yet they reacted significantly less frequently to common extrinsic allergens.     

Framing the future of antifungals in atopic dermatitis

Atopic dermatitis (AD) is a frequent chronic inflammatory skin disease. Some fungal colonization or infection of the skin may exacerbate AD severity, particularly the so-called head and neck variant. In addition, excessive intestinal colonization by Candida albicans may represent an additional triggering factor. Hence, there is a rationale to use antifungals in selected AD patients. Early trials with topical ketoconazole in head and neck AD showed a decrease in Malassezia colonization, but no significant improvement was observed in the clinical severity. In contrast, clinical improvement and decreased serum IgE were obtained in patients with positive Malassezia radioallergosorbent tests (RASTs) who were treated by oral ketoconazole. Some preliminary data suggested that oral itraconazole treatment in AD patients reduced the need for topical corticosteroids, provided clinical improvement particularly in head and neck AD, reduced the cutaneous and intestinal fungal colonization that may trigger AD, reduced the percentage of positive Malassezia cultures and demonstrated a decrease in C. albicans and Malassezia RAST values. Furthermore, beside its antifungal action, itraconazole in part relieves pruritus and inflammation. In conclusion, oral itraconazole treatment can alleviate AD severity in selected patients. Fluconazole is also effective. Further research is warranted to identify whether the load in skin surface fungal agents, the fungal RAST values and specific prick testing should be assessed in order to optimize the antifungal management in AD patients.     

Systemic ketoconazole for yeast allergic patients with atopic dermatitis

BACKGROUND: Adult patients with atopic dermatitis (AD), especially with the head-neck distribution, are often sensitized to the lipophilic yeast Malassezia furfur/Pityrosporum orbiculare, which is considered to contribute to the pathogenesis of the dermatitis. OBJECTIVE: Evaluation of the efficacy of oral ketoconazole on immunological and clinical parameters in yeast allergic adult patients with AD. STUDY DESIGN: Randomized double-blind placebo-controlled study. SUBJECTS: Twenty-nine patients with specific IgE antibodies to M. furfur/P. orbiculare and with elevated serum IgE participated in the investigation. Fifteen subjects were treated with 200 mg ketoconazole daily and 14 received placebo for 3 months. Betamethasone cream was allowed as supplementary therapy and the consumption was registered. The clinical score (SCORAD), total serum IgE and specific IgE antibodies to M. furfur/P. orbiculare, Candida albicans and Dermatophagoides pteronyssinus were monitored at the starting point and by the end of the first and third month. RESULTS: In the actively treated group the levels of specific IgE to M. furfur/P. orbiculare and C. albicans as well as total serum IgE decreased significantly. Sensitization to D. pteronyssinus was not influenced. The clinical score decreased in both groups, and the improvement was correlated to the consumption of topical steroids in the control group but not in the ketoconazole group.     

The natural history of sensitizations to food and aeroallergens in atopic dermatitis: a 4-year follow-Up

The natural history of atopic dermatitis (AD) is variable. Generally the dermatitis disappears during the first years of life, but it is often followed by the appearance of allergic respiratory diseases (ARDs). Our aim was to establish the risk factors for developing an ARD in children with AD. We followed up for 4 years 78 children (51 boys, 27 girls) with mild (26%), moderate (48%), and severe (26%) AD (clinical score proposed by Rajka and Langeland). In all the patients IgE serum levels were checked and skin prick tests (SPTs) were performed at the first examination. The SPTs were repeated in 68 children at the end of the study. The children with severe AD had significantly higher IgE serum levels than those with mild or moderate AD. SPTs at the first observation were positive in 47% of cases, mostly in patients with severe AD, with a prevalence of food allergens, particularly in younger patients. At the second observation, SPTs were positive in 65% of cases, including 100% of children with severe AD. Inhalants were the most common allergens. An ARD appeared in 38% of all patients: in 75% of those with severe AD and in 54% of those with a positive first SPT. Allergic screening should be carried out at an early age, especially in severe AD, since SPT positivity to food allergens, associated with severe clinical AD symptoms and a high IgE serum level, identifies those children ages 0-3 years at high risk of development of ARD.     

The role of Malassezia in atopic dermatitis affecting the head and neck of adults

Atopic dermatitis is a common chronic skin condition. A subset of patients with head and neck dermatitis may have a reaction to Malassezia flora fueling their disease. Although there are no documented differences in Malassezia species colonization, patients with head and neck atopic dermatitis are more likely to have positive skin prick test results and Malassezia-specific IgE compared with healthy control subjects and patients with atopy without head and neck dermatitis. There is no clear relationship with atopy patch testing. The reaction to Malassezia is likely related to both humoral- and cell-mediated immunity. Clinically, Malassezia allergy may be suspected in patients with atopic dermatitis and: (1) head and neck lesions; (2) exacerbations during adolescence or young adulthood; (3) severe lesions recalcitrant to conventional therapy; and (4) other atopic diseases. There is literature to suggest that these patients will benefit from a 1- to 2-month course of daily itraconazole or ketoconazole followed by long-term weekly treatment.     

Diagnostic Usefulness of the Serum-Specific IgE, the Skin Prick Test and the Atopy Patch Test Compared with That of the Oral Food Challenge Test

Background

Atopic dermatitis (AD) is frequently associated with food allergies. In addition to the skin prick test (SPT) and serum-specific IgE, the atopy patch test (APT) has been introduced as a diagnostic procedure for food allergies.

Objective

Our aim was to evaluate the diagnostic value of the APT, the SPT and the serum-specific IgE levels compared with that of oral food challenge test against milk and egg in AD patients.

Methods

We conducted the SPT and APT, and determined the serum-specific IgE levels against milk and egg antigens for 101 patients. Oral food challenge tests were conducted for 86 out of 101 AD patients. The sensitivity, specificity and positive and negative predictable values were calculated for all the tests.

Results

Twenty-five patients were positive to oral food challenges. The sensitivity of the APT for milk was 66.7%, while the figures for the SPT and the serum-specific IgE were 35.5% and 14.2%. The sensitivity of the APT for egg was 50%, while that for the SPT and serum-specific IgE were 21.4% and 6.7%.

Conclusion

We were able to conclude that the APT test seems to be a valuable additional tool for the diagnostic method of food allergies in AD.     

Selective cloning of allergens from the skin colonizing yeast Malassezia furfur by phage surface display technology.

The yeast Malassezia furfur, also known as Pityrosporum orbiculare (ovale), is part of the normal microflora of the human skin but has also been associated with different skin diseases including atopic dermatitis. More than 50% of atopic dermatitis patients have positive skin test and specific IgE to M. furfur extracts; however, the pathophysiologic role of these IgE-mediated reactions in the development of the disease remains unknown. The yeast is able to produce a wide panel of IgE-binding proteins, variably recognized by sera of individual patients. In order to assess the contribution of individual components to the disease, highly pure allergen preparations are required. We have cloned M. furfur allergens from a cDNA library displayed on the phage surface, sequenced the inserts and produced recombinant proteins in Escherichia coli. Phage displaying IgE-binding proteins were selectively enriched from the library using IgE from a M. furfur-sensitized atopic dermatitis patient as a ligand. We were able to identify five different inserts coding for IgE-binding polypeptides. Three of the sequenced cDNA encode incomplete gene products with molecular masses of 21.3 kDa (MF 7), 14.4 kDa (MF 8), and 9.7 kDa (MF 9), respectively, having no sequence similarity to known proteins. The other two cDNA encode allergens of 18.2 kDa (Mal f 5) and 17.2 kDa (Mal f 6). Mal f 5 shows significant homology to M. furfur allergens Mal f 2, Mal f 3 and an Aspergillus fumigatus allergen Asp f 3. Mal f 6 has significant homology with cyclophilin. All of the recombinant polypeptides were capable of binding serum IgE from atopic dermatitis patients in immunoblotting experiments. The availability of pure recombinant M. furfur allergens will allow the careful investigation of the role of IgE-binding proteins in atopic dermatitis.     

Hyperkeratotic head and neck Malassezia dermatosis

BACKGROUND: Pityriasis versicolor (tinea versicolor) is a common skin disorder due to Malassezia usually affecting adolescents and young adults, more frequently in the tropics. Facial involvement, isolated or not, is not frequent in white adults. OBJECTIVE: Here, we report a possible atypical hyperkeratotic form of dermatosis of the face, in two young immunocompetent Caucasian patients, particularly recalcitrant to therapy. RESULTS: Skin scrapings grew yeasts belonging to the genus Malassezia, including both M. globosa and M. sympodialis. This unusual variant needs long-term therapy with systemic and topical imidazoles together with facial cleansing. CONCLUSION: We propose the name hyperkeratotic head and neck Malassezia dermatosis for this distinctive clinical entity. This variant of pityriasis versicolor should be considered in the differential diagnosis of seborrheic dermatitis and dermatitis neglecta.     

Late-onset of IgE sensitization to microbial allergens in young children with atopic dermatitis

Background  A significant proportion of young children with atopic dermatitis (AD) is sensitized to microbial allergens, which play a potential role in the pathogenesis of AD inflammation.
Objective  To study the timing of IgE sensitization to microbial allergens including staphylococcal superantigens, Malassezia species and Candida albicans in young children with AD.
Method  Specific IgE antibodies to staphylococcal superantigens, Malassezia species, C. albicans and control inhalant/food allergens were measured in 53 young children with mild to moderate AD. The presence of IgE sensitization relative to age (≥ 3 years vs. < 3 years) was analysed by logistic regressions.
Results  IgE sensitization to the staphylococcal superantigen group, Malassezia species and C. albicans was significantly associated with older age in children with AD [ P  =   0·02, odds ratio (OR) 4·9; P  =   0·02, OR 4·7; and P  =   0·05, OR 4·0, respectively].
Conclusion  IgE sensitization to microbial allergens is associated with an older age group in young children with mild to moderate AD.