S. aureus and SEs have important roles in the exacerbation and prolongation of AD.

Mutations in ceramide biosynthesis pathways have been implicated in a few Mendelian disorders of keratinization, although ceramides are known to have key roles in several biological processes in skin and other tissues. Using whole-exome sequencing in four probands with undiagnosed skin hyperkeratosis/ichthyosis, we identified compound heterozygosity for mutations in KDSR, encoding an enzyme in the de novo synthesis pathway of ceramides. Two individuals had hyperkeratosis confined to palms, soles, and anogenital skin, whereas the other two had more severe, generalized harlequin ichthyosis-like skin. Thrombocytopenia was present in all patients. The mutations in KDSR were associated with reduced ceramide levels in skin and impaired platelet function. KDSR enzymatic activity was variably reduced in all patients, resulting in defective acylceramide synthesis. Mutations in KDSR have recently been reported in inherited recessive forms of progressive symmetric erythrokeratoderma, but our study shows that biallelic mutations in KDSR are implicated in an extended spectrum of disorders of keratinization in which thrombocytopenia is also part of the phenotype. Mutations in KDSR cause defective ceramide biosynthesis, underscoring the importance of ceramide and sphingosine synthesis pathways in skin and platelet biology.

Spiny keratoderma is a dermatosis consisting of multiple projections located on the palms and soles, with a distinct histology characteristic of a parakeratotic column above a hypogranular epidermis. We report six cases discovered within a year and review the present literature on spiny keratoderma. The average age of the patients was 57 years. Fifty-seven percent of the patients were male and forty-three percent were female. The duration of lesions ranged from 4 months to 40 years. Symptoms were variable, however, lesions were often unnoticed by the patient. The location of the lesions involved the palms and soles or the palms alone. Past medical history was significant for hypertension and hyperlipidemia treated with HMG-CoA reductase inhibitors. Lesions often occurred in patients involved in manual labor. Spiny keratoderma is a relatively common under-reported dermatosis found most often in older patients with history of manual labor and is possibly related to treatment with HMG-CoA reductase inhibitors.

Eczematous skin lesions of atopic dermatitis (AD) are usually colonized densely with Staphylococcus aureus [1,2]. A correlation between the severity of eczematous lesions and colonization with S. aureus has been demonstrated [2]. S. aureus can produce superantigenic exotoxins which may be involved in the exacerbation of AD. Exotoxins with superantigenic properties have been shown to be produced in S. aureus isolates from 24 of 42 AD patients (57.1%) in one study [3] and 24 of 37 AD patients (64.9%) in another study [4]. The strains isolated from severe AD have been shown to produce α-toxin [5] in 20 of 20 patients (100%), β-toxin in 12 of 20 patients (65%), and δ-toxin in 17 of 20 patients (85%) [6]. We examined the prevalence of producers of enterotoxins (SE) and toxic shock syndrome toxin-1 (TSST-1) production among strains of S. aureus isolated from AD patients and compared this with the clinical symptoms exudation, swelling and erythema.Patients who fulfilled the criteria of Hanifin and Rajka for AD [7] were examined for bacteria, and only patients with positive S. aureus culture were enrolled. A group of 76 patients with AD (34 males and 42 females; mean age (± SD) 21.9 ± 9.6 years, range 2-48 years) were studied, of whom 61 were avaiblable of culture of lesions of the face only and 15 were available for culture of lesions of the neck only. The lesions were classified as with or without exudation, with or without swelling, and red or light/dark-red erythema.We scrubbed a 3-cm diameter circular area of the AD lesions five times with sterilized swabs (Nissui, Tokyo, Japan) soaked in sterilized saline solution and smeared the swabs on culture dishes (15 × 60 mm; Sumitomo Bakelite, Tokyo, Japan) containing 10 ml Staphylococcus Medium No-110 (Nissui, Tokyo, Japan). The colonies were mature after 48 h incubation at 37°C, and the grown colonies were evaluated. Four colonies were randomly selected from each culture and inoculated onto Mueller Hinton Medium (Difco, Detroit, Mich.). After an additional 24 h at 37°C, an aliquot of each colony was tested by Staphaurex (rapid latex test kit for the identification of S. aureus; Murex Diagnostics, Dartford, UK) and the positive strains were regarded as S. aureus. The total number of identified S. aureus strains was 286, and 18 strains were excluded because the Staphaurex test was negative. After centrifugation of each culture at 500 g for 20 min, 25 µl of the supernatant and 25 µl of the tenfold diluted supernatant solutions were placed in 96-well tissue culture dishes (Becton Dickinson, NJ.). Standard exotoxins and control latex sensitized by normal rabbit immunoglobulin G (IgG) (Denka Seiken, Tokyo, Japan) were placed in separate wells as positive and negative controls. Latex particles (25 µL) coated with specific rabbit IgG against staphylococcal enterotoxins (SEA, SEB, SEC, SED) and TSST-1 (Denka Seiken, Tokyo, Japan) were added to the culture wells. After 20 h incubation at room temperature, the wells were checked for agglutination.Comparison between the production of...

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