Cutaneous granulomas in ataxia telangiectasia and other primary immunodeficiencies: reflection of inappropriate immune regulation?

BACKGROUND: Non-infective cutaneous granulomas with unknown pathogenesis occur in various primary immunodeficiencies (PIDs) including ataxia telangiectasia (A-T). OBJECTIVE: To find a common immunological denominator in these cutaneous granulomas. METHODS: The dermatological and immunological features of 4 patients with A-T and cutaneous granulomas were described. The literature on skin granulomas in A-T and in other PIDs is reviewed. RESULTS: All 4 A-T patients had progressive granulomas on their limbs and showed decreased IgG and IgA concentrations with normal IgM levels. They had a marked decrease in B cells and naïve T cells coinciding with the appearance of the cutaneous granulomas. Similar B- and T-cell abnormalities were described in patients with other PIDs with skin granulomas. CONCLUSIONS: We hypothesize that the pathogenesis of these skin granulomas is related to immune dysregulation of macrophages due to the absence of naïve T cells with an appropriate T-cell receptor repertoire and the unopposed activity of γδ T cells and/or natural killer cells.

Juvenile psoriasis in European and Asian children: similarities and differences.

BACKGROUND: The first manifestations of psoriasis begin in childhood in more than one-third of patients. However, epidemiological data of juvenile psoriasis are lacking. OBJECTIVES: To compare Dutch (NL group) and Singaporean (SG group) children with psoriasis with the aim of studying the characteristics of juvenile psoriasis and to highlight similarities and differences between these different ethnic groups. METHODS: Data were collected from 207 patients younger than 18 years diagnosed with psoriasis from Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands and the National Skin Centre, Singapore. RESULTS: A striking difference in familial distribution was found, with more Dutch children having an affected family member (73·3% vs. 13·6%). Presence of itch and triggering factors were more common among Dutch children (80% vs. 14·2% and 33·3% vs. 7·4%, respectively). However, both groups shared similar triggering factors like stress and infections. Other similarities included mean age at presentation (NL group 11·3 years; SG group 14·1 years) and gender ratio (NL group, M/F 1 : 1·1; SG group, M/F 1 : 1·4). Plaque psoriasis was the most common type in both cohorts while guttate and pustular psoriasis were rare. In both groups, the head, followed by the limbs, was the most common site involved. Similar proportions of children in both countries had nail involvement and psoriatic arthritis was rare. CONCLUSIONS: The disparity in familial distribution may point to genetic differences between the two groups. Further studies to evaluate this difference in familial distribution may contribute to the understanding of the pathogenesis of psoriasis.

Prurigo pigmentosa: a report of two cases that responded to minocycline.

Prurigo pigmentosa (PP) is an unusual pruriginous dermatosis of unknown aetiology and is often misdiagnosed. We report two people (a 16-year-old Chinese boy and a 21-year-old Chinese woman), who presented with clinicopathological features consistent with PP. Both patients were successfully treated with minocycline. Better knowledge of this disease will lead to early recognition and appropriate treatment.

Solitary plaque mycosis fungoides on the penis responding to topical imiquimod therapy.

Mycosis fungoides (MF) presenting in the genitalia is rare. We report a case of long-standing penile MF in a young man. Commonly used treatments for limited plaque MF include topical corticosteroids and ultraviolet light therapy. There are a few anecdotal reports on the use of topical imiquimod in MF. Our patient responded well and remained in complete remission after treatment with topical imiquimod.