Association between melanoma and dermal mast cell prevalence in sun-unexposed skin.

BACKGROUND: Both exposure to intermittent intense sunlight during childhood and ultraviolet (UV) radiation-induced immunomodulation have been directly associated with melanoma development. In mice, the prevalence of dermal mast cells determines susceptibility to UVB-induced systemic suppression of contact hypersensitivity responses and thus may affect immunological responses to melanoma antigens. OBJECTIVES: To determine the relevance of murine studies of dermal mast cell prevalence to human melanoma pathogenesis. METHODS: The prevalence of mast cells was examined in sun-unexposed buttock skin of 45 melanoma patients and 68 control volunteers who had no history of skin cancer development. Buttock skin was studied because mast cell prevalence is stable with ageing and the confounding effects of environmental UV exposure are minimized. RESULTS: Using tissue immunostaining, the buttock skin from melanoma patients had a significantly higher dermal mast cell prevalence (mean +/- SEM 38 +/- 2 mast cells mm(-2)) than controls (32 +/- 2 mast cells mm(-2)) (P = 0.02). Analysis by binary logistic regression showed that the association between mast cell prevalence and melanoma outcome was not significantly altered by skin phototype. CONCLUSIONS: The immunomodulatory effects of mast cell products in UV-irradiated skin may contribute significantly to the initiation and development of human cutaneous malignant melanoma.

Tea tree oil reduces histamine-induced skin inflammation.

BACKGROUND: Tea tree oil is the essential oil steam-distilled from Melaleuca alternifolia, an Australian native plant. In recent years it has become increasingly popular as an antimicrobial for the treatment of conditions such as tinea pedis and acne. OBJECTIVES: To investigate the anti-inflammatory properties of tea tree oil on histamine-induced weal and flare. METHODS: Twenty-seven volunteers were injected intradermally in each forearm (study and control assigned on an alternating basis) with histamine diphosphate (5 microg in 50 microL). Flare and weal diameters and double skin thickness were measured every 10 min for 1 h to calculate flare area and weal volume. At 20 min, 25 microL of 100% tea tree oil was applied topically to the study forearm of 21 volunteers. For six volunteers, 25 microL paraffin oil was applied instead of tea tree oil. RESULTS: Application of liquid paraffin had no significant effect on histamine-induced weal and flare. There was also no difference in mean flare area between control arms and those on which tea tree oil was applied. However, mean weal volume significantly decreased after tea tree oil application (10 min after tea tree oil application, P = 0.0004, Mann-Whitney U-test). CONCLUSIONS: This is the first study to show experimentally that tea tree oil can reduce histamine-induced skin inflammation.

Subcutaneous fat necrosis of the newborn following hypothermia and complicated by pain and hypercalcaemia.

A female infant was delivered at term with complications of severe meconium aspiration and birth asphyxia. Surface cooling was performed in the first 24 hours as part of the management of her birth asphyxia. Woody erythema was noted at 24 hours, followed by the formation of red-purple nodules on the 6th day. Clinical findings in the first 24 hours were suggestive of cold panniculitis. However, clinical and histological findings progressed to be in keeping with the diagnosis of subcutaneous fat necrosis of the newborn (SCFN). Furthermore, the immediate postnatal period was complicated by pain resistant to treatment with opiates. Asymptomatic hypercalcaemia was noted on periodic testing at 7 weeks and treated by rehydration, diuretics, prednisolone, etidronate and a low-calcium and -vitamin D diet. A review of the clinical and histological findings of the relevant panniculitides occurring in the postnatal period is presented, as well as a review of the treatment of hypercalcaemia in SCFN.

Communications: high dermal mast cell prevalence is a predisposing factor for basal cell carcinoma in humans.

Ultraviolet B radiation (280-320 nm) can initiate skin cancer as well as suppress the immune system, thereby preventing the rejection of ultraviolet-B-induced tumors. Recently we reported that there was not only a correlation but also a functional link between dermal mast cell prevalence and susceptibility to ultraviolet-B-induced systemic immunosuppression in multiple strains of mice. In this study, we investigated whether increased dermal mast cell prevalence is a significant predisposing factor for basal cell carcinoma development in humans. In 21 Danes with a history of basal cell carcinoma and 20 control subjects of similar age, sex, skin phototype, and recreational sun exposure over the past 12 mo, dermal mast cell prevalence was quantified on non-sun-exposed buttock skin. We investigated this skin site in order to avoid any changes in mast cell prevalence caused by sun exposure and assumed that the prevalence of mast cells in buttock skin correlated with that at sun-exposed sites at critical times in the development of basal cell carcinomas. Patients with a history of basal cell carcinoma had a significantly higher median dermal mast cell prevalence than control subjects (p = 0.01, Mann-Whitney U ). No correlation was observed between dermal mast cell prevalence and age of basal cell carcinoma patients and control subjects. These results suggest that increased dermal mast cell prevalence is a predisposing factor for basal cell carcinoma development in humans. We hypothesize that mast cells function in humans, as in mice, by initiating immunosuppression and thereby allowing a permissive environment for basal cell carcinoma development.

Variable presentation of parvovirus B19 in a family.

This case report of the sequential presentation of parvovirus B19 in a family describes a 38-year-old woman initially presenting with 'gloves and socks' syndrome, along with her husband and five children who were also affected. A high clinical attack rate with prolonged illness and variable clinical presentations was demonstrated, including polyarthritis, erythema infectiosum and symptoms of a respiratory tract infection. In addition, the range of syndromes and clinical features of parvovirus B19 are presented.

Lichen planus.

Lichen Planus is a relatively common inflammatory dermatosis of unknown origin. The present review summarizes the histological and clinical features of lichen planus and variants, including lichenoid drug reactions, are described. Possible mechanisms of pathogenesis of lichen planus are reviewed. The development of malignancy in association with lichen planus and the association with hepatitis are discussed. Treatment options for the more difficult manifestations of lichen planus are proposed.

Comparison of the actions of kallidin and bradykinin in the skin of normal and psoriatic subjects.

With the recent development of selective drugs acting on the kinin system and the identification of a kallikrein-like enzyme from psoriatic blister fluid, there is now much interest in the possible role of kinins in psoriasis. We have examined the time-course of the inflammatory (weal and flare) responses to intradermal kallidin (lysbradykinin) and bradykinin in normal volunteers, and have compared the dose-response effect of these agents in normal volunteers and patients with psoriasis. Initially, normal subjects (n = 5) received coded intradermal injections of 50 microliters normal saline containing kallidin or bradykinin (0.1, 0.5, 1.0 and 5.0 micrograms). Weal volume, weal area and flare area were calculated at 5, 15, 30 and 60 min by measuring two perpendicular diameters and change in skinfold thickness. Weal and flare measurements were subsequently made at 15 and 5 min, respectively. Patients with psoriasis (n = 9) and normal subjects (n = 10) were given intradermal injections of kallidin (0.1 and 1.0 microgram) and bradykinin (0.1, 0.5 and 1.0 microgram) in clinically normal forearm skin, using histamine and normal saline as controls. The dose-response effects of kallidin on weal and flare responses in human skin were established in the study and compared with those of bradykinin. There was wide inter-individual variability for both agents and, although mean responses to the highest doses of kallidin and bradykinin were decreased in psoriatic skin, no significant differences were found between the psoriatic and normal group for kallidin, bradykinin or histamine. Hence, there do not appear to be any obvious altered vascular responses to kallidin or bradykinin in patients with psoriasis, despite the fact that kinins may be generated in psoriatic tissue.

A case of Grzybowski's generalized eruptive keratoacanthomas.

We report a case of Grzybowski's generalized eruptive keratoacanthoma which demonstrates the characteristic features of this rare condition. The recurring nature of the eruption each summer supports the suggestion that UV irradiation may act as a precipitating factor in eruptive keratoacanthoma.

Multiple clear cell acanthomas treated by cryotherapy.

Clear cell acanthoma is usually a solitary lesion. We report a patient with multiple lesions demonstrating the typical clinical and histological features of clear cell acanthoma, which responded well to treatment with liquid nitrogen.

Folliculitis in Down's syndrome.

Twenty-two male and 20 female adults with Down's syndrome were examined. Ten of the men and two of the women had a follicular rash consistent with Malassezia folliculitis. Oral itraconazole treatment produced a significant improvement in the rash, accompanied by a decrease in the skin Malassezia count. Clinical relapse occurred when therapy was discontinued, and was accompanied by return of the Malassezia yeasts.

Comparison of plasma prekallikrein levels in human skin blister and chamber fluids from volunteer subjects and psoriatic patients.

Suction blisters were successfully raised on lesional, perilesional and non-lesional skin of psoriatic patients. Similar blisters were created on the skin of volunteer subjects. A specific method has been established for the measurement of plasma prekallikrein, and validated for blister fluid, skin chamber fluid, plasma and synovial fluid. Combined levels of plasma prekallikrein and its active form were compared in blister fluids obtained from psoriatic patients and the volunteers. Significantly higher values for plasma prekallikrein were found in the non-lesional blister fluids of psoriatic patients when compared to the volunteer subjects.

Cutaneous abnormalities in anorexia nervosa.

Anorexia Nervosa (A.N.) is a relatively common eating disorder with well recognised psychological and physiological features. A study of 14 female patients with A.N. revealed a number of dermatological disorders, including lanugo hair, xeroderma and hyperpigmentation. Laboratory investigations revealed various abnormalities including elevated Beta-carotene levels, abnormal sex hormone and thyroid function. An unusual finding was the development of acne in a small subset of patients at the time of weight gain, during recovery from A.N. Anorexia Nervosa represents a useful model for the interaction between eating disorders, endocrine function and the skin.