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Photosensitivity in childhood is caused by a diverse group of diseases. It usually indicates idiopathic photodermatoses, first of all polymorphic light eruption. It may be an early symptom of genetic disorders such as porphyria or very rare genophotodermatoses. Photosensitivity secondary to topical or systemic external agents as well as photoexacerbated dermatoses is not so frequent in childhood. Here we present our experience with childhood photosensitivity skin diseases collected over a 40-year period.

Background: A failure in the apoptotic response after severe genomic damage could facilitate cell transformation and tumor development, and a constitutive overexpression of either p53 or bcl-2 protein in nonapoptotic tumor cells could signify a defective bax-mediated apoptosis. Objectives: To investigate whether a negative correlation occurs between these 2 proteins in nonmelanoma skin cancer and whether overexpression of either protein is associated with a low rate of spontaneous apoptosis. Design: Immunohistochemical study of nonmelanoma skin cancer archive material. Setting: University referral center. Patients: White patients with tumors on sun-exposed skin areas (ie, 17 basal cell carcinomas and 22 squamous cell carcinomas). Main Outcome Measures: Positivity for p53 and bcl-2 were scored semiquantitatively on 4 levels, and the percentages of apoptotic cells were determined. Results: A significant negative correlation between p53 and bcl-2 expression was found in the basal cell carcinomas, but not in the squamous cell carcinomas, largely attributable to the low level of bcl-2 staining in the squamous cell carcinomas. Squamous cell carcinomas have a significantly higher number of apoptotic cells than basal cell carcinomas: 1.1% vs 0.6%, respectively. This spontaneous apoptosis decreases with increasing bcl-2 (in basal cell carcinoma), whereas it does not appear to be related to p53 level expression. Conclusions: These results indicate that a disturbance in either p53 or bcl-2 suffices to enhance skin tumor formation by suppressing apoptosis; bcl-2 appears to reduce the rate of spontaneous apoptosis, but an aberrant p53 expression does not, and this factor may solely affect the apoptosis from exogenous genotoxicity. Arch Dermatol. 1997;133:599-602

The pathogenetic role of liver damage in photodermatoses induced by oral contraceptives was investigated. From among 121 cases with photodermatosis, it was in 4 cases of polymorphic light eruption-like dermatosis and in 2 cases of porphyria cutanea tarda that a longterm use of antibaby pills preceded the development of skin disease. Physical and biochemical studies of the liver of the patients suggested that the hepatotoxicity of the estrogen component of oral contraceptives can play a role not only in the pathomechanism of porphyric cases, but also in that of cases occurring with the clinical picture of polymorphic light eruption.

Repair of UV-light induced DNA damage and changes in the semiconservative DNA synthesis were studied by in vitro autoradiography in the skin of patients with lightdermatoses (polymorphous light eruption, porphyria cutanea tarda, erythropoietic protoporphyria) and xeroderma pigmentosum as well as in that of healthy controls. In polymorphous light eruption the semiconservative DNA replication rate was more intensive in the area of the skin lesions and in the repeated phototest site, the excision repair synthesis appeared to be unaltered. In cutaneous porphyrias a decreased rate of the repair incorporation could be detected. Xeroderma pigmentosum was characterized by a strongly reduced repair synthesis.

Prostaglandin F2α (PGF2α) as a possible mediator was studied. Its plasma content was determined by radioimmunoassay. Changes in the DNA synthesis were followed by autoradiography. In active polymorphous light eruption (PLE) and porphyria cutanea tarda (PCT) a remarkable increase (over 300 pg/ml) in plasma content occurred, especially in cases involving large skin areas. Values returned to normal in remission. PGF2α administered i.d., significantly increased the DNA synthesis of the epidermal cells 48 h after injection similar to the effect of three minimal erythema dosis UV-irradiation. This was more pronounced in PLE patients than in controls. These findings suggest some role of PGF2α in producing the inflammatory and perhaps proliferative components of the skin symptoms in PLE. PGF2α — in parallel to literary data concerning PGE — seems to be a mediator of UV-induced changes in DNA synthesis of the epidermal cells.

The relationship between porphyria and liver damage was studied in 24 cases with porphyria cutanea tarda treated with Ippen's cure. In the history of 22 patients an excessive alcohol ingestion, in that of 2 other patients permanent medication with antibaby pills could be demonstrated. Conclusions for the condition of the liver parenchyma were derived from the serum activities of mitochondrial GLDH and lysosomal arylsulfatase. The degree of the mesenchymal reaction of the liver was estimated by the quantitative assay of serum immunoglobulins. On the basis of the results a liver damage involving both the parenchyma and mesenchyma was proved in each patient. The immunoglobulogram showed a considerable resemblance to that of 16 patients with chronic alcoholic hepatopathy. The IgG and IgA values tendentiously decreased after a successful Ippen's cure. It is probable that the products of pathological porphyrin metabolism contribute to the aggravation of the chronic inflammatory liver process. Presumably the serial phlebotomies influence the activity of the mesenchymal reaction of the liver favourably by means of reducing its porphyrin and iron depot. It appears that valuable information can be obtained about the nature and course of the liver damage also in PCT by the help of immunoglobulin and enzymatic assays.