Acne agminata is a papulo-pustular eruption typically affecting the face of young adults and characterized histologically by the presence of caseating granulomata in the dermis. We now describe two adults who developed the condition in the axillae.

Congenital deficiency of beta 2 integrin leucocyte adhesion molecules is a rare immunodeficiency and is often fatal. Neutrophils are unable to bind to ligands on the endothelium, and so cannot leave the circulation during inflammation or infection. When leucocyte adhesion deficiency (LAD) is caused by abnormally low expression of beta 2 integrins, it is termed LAD type 1. We describe a 5-year-old girl with a history of recurrent bacterial infections since early childhood who developed necrotic skin ulcers resembling pyoderma gangrenosum and a persistent circulating neutrophilia. Histologically, the lesions showed deep ulceration with a diffuse lymphohistiocytic infiltrate, but with a relative sparsity of neutrophils. Subsequent investigation revealed a complete absence of CD11a/CD18 beta 2 integrins on the surface of the patient's neutrophils, confirming the diagnosis of LAD type 1. The ulcers responded to treatment with oral prednisolone and colchicine.

Somatic mutations within c-kit have been reported in individuals with mastocytoses, including urticaria pigmentosa (UP). We have identified three siblings with UP. We aimed to determine whether the c-kit proto-oncogene was playing a part in the aetiology of UP in these three siblings. Using seven microsatellite repeat markers spanning an 8-cM interval encompassing the c-kit gene we followed the transmission of the c-kit gene in this family. Furthermore, single-strand conformation polymorphism analysis was used to scan exon 17 of the c-kit gene for mutations in genomic DNA of all family members and somatic DNA extracted from skin of the eldest affected sibling, the proband. No mutations were found in exon 17 in either genomic DNA of all family members or somatic DNA of the proband. Patients with UP have been shown to possess somatic mutations of the c-kit gene. However, this locus has been excluded as playing a part in the three siblings examined here in whom a second gene locus must be determining their UP. Therefore, this study emphasizes genetic heterogeneity in UP. Future study to identify primary molecular determinants of UP should include affected sib-pair studies.

A case of Dowling-Degos disease coexisting with hidradenitis suppurativa is described. We propose that the follicular occlusion inherent in Dowling-Degos disease may predispose to the development of hidradenitis suppurativa.

Angiogenesis is a recognized event in psoriasis. Previous ultrastructural studies have demonstrated lymphatic capillaries extending high into the dermal papillae. Using the novel method of fluorescence microlymphography which permits visualization of upper dermal initial lymphatics in vivo we tested the hypothesis that lymphangiogenesis exists within plaque psoriasis. Six patients underwent fluorescence microlymphography with fluorescein isothiocyanate-dextran administered intracutaneously within a psoriatic plaque on the leg. Stereological analysis permitted quantification of the lymphatic network opacified both within (lesional) and without (perilesional) the plaque. Results showed a greater spread of tracer from the depot into perilesional skin than into the plaque (P < 0.006). The mean length of lymphatics per unit area at increasing distance from the centre of the depot was also increased for the perilesional skin, 10.5 +/- 1.9/cm2 (mean +/- SEM), compared with lesional skin, 3.06 +/- 0.8/cm (P < 0.001). The cumulative lymphatic length was also greater in perilesional, 22 +/- 7.3 cm2, compared with lesional skin, 3.6 +/- 0.3 cm (P < 0.006). Fluorescence microlymphography has proved to be an effective in vivo technique for the assessment of the dermal microlymphatics in psoriasis. Stereology provided quantitative analysis of the lymphatic network visualized. Overall, there is a greater network of lymphatics in perilesional compared with lesional skin in patients with plaque psoriasis. This finding is at odds with the accepted view that the lymphatic dermal vessels are increased within the psoriatic plaque.

The role of angiogenesis in tumour growth and metastasis is well established. However, investigations of tumour microcirculation to date have used either biopsy material from human tumours, or animal models in vivo. We have studied the tumour microcirculation in vivo in human skin cancers using video-microscopy to examine 12 basal cell carcinomas (BCCs) on the head and neck of 11 patients, and compared the vessels with those seen in the peri-lesional skin, and in normal control skin on the opposite side of the body. The vessels seen within the BCCs were markedly abnormal qualitatively, forming bizarre, disorganized patterns. Quantitative analysis revealed that the mean diameter (+/-standard deviation) of the largest vessel was significantly greater within the BCC (0.086+/-0.029 mm) than that in the control skin (0.034+/-0.012 mm) (P<0.001). The area fraction, a measure of the area of tissue occupied by vessels, was increased highly significantly within the BCCs (0.158+/-0.038) compared with both peri-lesional skin (0.029+/-0.012) and control skin (0.027+/-0.010) (P<0.001). Length density, the length of blood vessel per unit area of tissue, was also highly significantly greater within the lesion (210.22+/-66.05 cm(-1)) compared to peri-lesional (27.10+/-15.67 cm(-1)) and control skin (28.27+/-15.81 cm(-1)) (P<0.001). This is the first study to have demonstrated that BCCs possess a distinct tumour microcirculation which can be observed directly, and assessed quantitatively. Prospective studies of tumour progression, possibly after intervention with angiogenesis inhibitors, are possible.

Angiogenesis was demonstrated in BCC in humans in vivo, and to a lesser extent in AK.

Skin cancer is increasingly common, and the skills involved in its diagnosis should be promoted in UK medical schools. However, there has been no scientific evaluation of the teaching methods employed by dermatology departments. The aim of this study was to evaluate, using traditional audiovisual methods, the impact of an illustrated booklet on skin cancer, coupled with a lecture, on undergraduates' diagnostic skills. The ability of 27 final-year medical students to recognize a variety of skin lesions, using projected images from clinical slides, was assessed. They were tested without warning on two occasions. Immediately after the first test, students were given an illustrated booklet on skin tumours and pigmented lesions which was supplemented with a lecture based on the booklet. Two weeks later, a second test was employed using a series of slides deemed to be of equal diagnostic difficulty. Our results showed a significant increase in the median number of correct diagnoses between the first and second tests (P < 0.001). However, there remained wide variation at the second test in the percentage of correct answers (30 to 80%) amongst students. Our study highlights the need to develop effective methods for improving the diagnostic skills of undergraduates in dermatology, and the importance of evaluating teaching methods. The methods of evaluation, such as ours, can be simple and inexpensive.