J.L.M. Hawk

The presence of neutrophils in human cutaneous ultraviolet‐B inflammation

We report the first observation of neutrophils in the dermal inflammatory infiltrate in human skin soon after moderate ultraviolet‐B (UVB) irradiation. Thus human UVB‐induced cutaneous inflammation, in this as in other respects, appears to resemble other human acute inflammatory responses to injury.

Polymorphic light eruption: prevalence in Australia and England

Summary The prevalence and clinical characteristics of polymorphic light eruption were assessed by a questionnaire survey of 172, 196 and 182 subjects in Perth, Ballarat and London, respectively. The prevalence was 5·2% in Perth (latitude 32°), 3·6% in Ballarat (37·5°) and 14·8% in London (51·5°). The age distribution (mostly first three decades) and male: female ratio (1:3) was similar for affected individuals in all three areas. Development of tolerance during the summer was more common in Perth (66·7%) and Ballarat (71·4%) than in London (40·7%).

Contact and photocontact sensitization in chronic actinic dermatitis: sesquiterpene lactone mix is an important allergen

Summary Eighty‐nine patients with chronic actinic dermatitis (CAD) were retrospectively studied: 69 (78%) male and 20 (22%) female, with mean ages of 66 and 64 years, respectively; nine (10%) were dark skinned. Eight (9%) were abnormally sensitive to UVB wavelengths alone, 74 (83%) to UVB and UVA, and seven (8%) to UVB, UVA and visible radiation. Eighty‐six patients were patch tested to an extended standard European series of contact allergens, including in 80 cases a 0.1% mix of three sesquiterpene lactones, and photopatch tested to a standard photopatch series. Sixty‐four of these 86 patients (74%) had positive patch or photopatch tests; 36% (29 of 80) were sensitive to the sesquiterpene lactone mix, 21% (18 of 86) to fragrance compounds, 20% (17 of 86) to colophony, and 14% (12 of 86) to rubber chemicals. Ten (12%) had positive photopatch tests; five (6%) to musk ambrette, six (7%) to sunscreens and one to both. Fourteen of the eighty‐nine patients with CAD (16%) had preceding endogenous eczema. In 18 of 86 patients (21%), CAD occurred alone, with neither detectable contact nor photocontact allergy, nor a preceding history of endogenous eczema. This study confirms the association between Compositae (sesquiterpene lactone) dermatitis and CAD.

Polymorphic light eruption: an immunopathological study of evolving lesions

Polymorphic light eruption (PLE) papules were successfully induced on previously affected sites in 11 out of 14 patients with PLE 4–20 h after single exposures to suberythemogenic doses of solar simulated radiation. Histological examination of biopsies performed 1 h, 5 h, 24 h, 72 h and 144 h post‐irradiation revealted onset within 5 h of perivascular cellular infiltration. The infiltrate was dominated by lymphocytes in both early and established lesions, without evident epidermal pathology. Immunohistochemistry demonstrated a predominance of CD4 + cells in lesions up to 72 h post‐induction, but later biopsies were dominated by a CD8 + infiltrate. Significantly increased numbers of dermal macrophages and CD1b + cells were detected 1 h and 5 h post‐irradiation, respectively. These findings are consistent with a delayed type hypersensitivity response underlying the pathogenesis of polymorphic light eruption.

Oral psoralen photochemotherapy in severe childhood atopic eczema: an update

Over a 6‐year period, oral psoralen photochemotherapy (oral PUVA) has been used to treat 53 children (mean age 11. 2 years) with severe atopic eczema unresponsive to other therapy. Twiceweekly treatment resulted in clearance or near‐clearance of disease in 39 (74%) after a mean of 9 weeks. Thirty‐two (82%) of these 39 children were subsequently able to achieve remission of disease following gradual withdrawal of treatment: the mean duration of treatment to remission was 37 weeks; the mean cumulative UVA dose was 1118 J/cm2 and the mean number of treatments was 59. Twenty‐two remain in remission a year after discontinuing treatment. Short‐ and medium‐term adverse effects, other than occasional intolerance of treatment, have not been prominent.

The quality of life of 790 patients with photodermatoses

Background  Polymorphic light eruption and erythropoietic protoporphyria (EPP) have been demonstrated to have a moderate and large impact on the quality of life (QoL) of patients, respectively. However, there is little information available about the impact of other photodermatoses on QoL.

Low-dose ultraviolet-B irradiation depletes human epidermal Langerhans cells

We have examined the effects of low‐dose monochromatic UVB irradiation (295±5 nm), biologically equivalent to that generally incident on the skin during a 12‐session sun‐bed course, on the expression of the CDla epidermal Langerhans cell surface marker in human skin in vivo. In five subjects, 1.5 minimal erythema doses (MEDs) at 295 nm depleted its expression by 50%. In five further subjects, a single 1.5 MED dose, 1.5 MEDs in 10 equal fractions on alternate days, and a single 1.5 MED dose at one‐tenth the previously used irradiance, delivered to separate sites, also led to variable but significant depletion of CD la expression of around‐30–50%. Thus, low‐dose UVB irradiation, whether received rapidly or slowly, appears significantly and approximately equally to deplete human epidermal Langerhans cell numbers as measured by CDla expression.

The efficacy of psoralen photochemotherapy in the treatment of aquagenic pruritus

Summary Psoralen photochemotherapy (PUVA) was effective in the treatment of five patients with aquagenic pruritus, associated in one with polycythaemia rubra vera and in another with the myelodysplastic syndrome. Relapse occurred within 2–24 weeks when treatment was discontinued. Maintenance therapy or a further course of PUVA was necessary to maintain remission. This requirement may limit the value of the therapy.

A study of the kinetics and pattern of E-selectin, VCAM-1 and ICAM-1 expression in chronic actinic dermatitis

Summary It has been postulated that chronic actinic dermatitis (CAD), an eczematous photodermatosis. is a type IV hypersensitivity reaction. Expression of adhesion molecules on dermal blood vessels is critical to the recruitment of inflammatory cells into the skin: the pattern and kinetics of upregulation of these molecules in the skin differ following ultraviolet irradiation and delayed hypersensitivity reactions. We therefore investigated the kinetics of expression of endothelial leucocyte adhesion molecules (E‐selectin) vascular‐cell adhesion molecules 1 (VCAM‐1) and intercellular adhesion molecule 1 (ICAM‐1) in CAD lesions induced by suberythemal solar‐stimulated radiation, by immunohistochemical staining of biopsies taken at 1‐168 h after irradiation. In control, unirradiated skin from CAD patients, baseline vessel‐associated and interstitial ICAM‐1, and vessel‐associated VCAM‐1 were noted; focal keratinocyte lCAM‐1 expression was observed in two of the five patients. Endothelial E‐selectin, and vessel‐associated and interstitial VCAM‐1 expression, were upregulated in induced lesions by 1‐5 h in all patients, and remained elevated at 120‐168 h. Vessel associated, dermal interstitial, and keratinocyte ICAM‐1 expression was upregulated in all patients at 24h, and remained increased at 120‐168h. These findings differ from those observed following ultraviolet irradiation of normal skin, and resemble those seen in normal skin during a delayed‐type hypersensitivity reaction, supporting the hypothesis that CAD involves a type IV response to an as yet unidentified photo‐induced antigen.

Homozygous variegate porphyria: a case report

Homozygous variegate porphyria is described in a 14‐year‐old girl with a unique clinical presentation of photosensitivity from the second year of life, mental retardation, clinodactyly, and normal growth rate. The erythrocyte protoporphyrin concentration was raised with the protoporphyrin being predominantly zinc‐chelated, which appears to be characteristic for all homozygous hepatic porphyrias. Protoporphyrinogen oxidase activity in lymphoblasts was decreased in both patient and parents despite the latter having normal porphyrin excretion.