Israel Medical Association Journal

Background: Solar urticaria (SU) is a rare and disabling photodermatosis. SU typically manifests as urticarial wheals and erythema appearing shortly after sun exposure. SU is often initially diagnosed clinically with subsequent confirmation through photoprovocation tests. Early diagnosis is important for correct management of patients.

Objective: To present the clinical features of three cases of atypical presentation of SU and to discuss possible underlying mechanisms.

Methods: We report a series of three patients who presented with transient pruritic erythema without wheals after sun exposure. All patients had photoprovocation tests conducted to confirm SU diagnosis and to determine their action spectra. Treatment outcomes were recorded.

Results: All three patients developed classical manifestations of SU during photoprovocation tests within the UVA1 spectrum. Two patients required high-dose irradiation to provoke urticaria.

Conclusions: Erythema without urticaria can be the primary manifestation of SU, especially in countries with sunny climates where natural skin hardening is common. Such cases require a high index of suspicion for SU and highlight the importance of photoprovocation testing to confirm the diagnosis.

Background: Frozen section (FS) is often performed when histopathological evaluations are urgently required for implementation of therapeutic measures. In dermatology, this method is most commonly used to evaluate excision margins of tumors. FS are also routinely employed to differentiate toxic epidermal necrolysis from staphylococcal scalded skin syndrome. However, little is currently known about the performance of FS in the diagnosis of inflammatory dermatoses.

Objectives: To compare histopathological diagnoses in a series of patients with a clinical diagnosis of an inflammatory dermatosis for which FS and paraffin-section (PS) specimens were obtained on the same day.

Methods: We conducted a single-center retrospective analysis of 43 cases. All histological slides were reviewed by a single dermato-pathologist. Concordance was calculated between FS and PS.

Results: Patients were divided into three groups according to diagnosis: papulosquamous diseases (group I), drug eruptions (group II), and a heterogeneous group (group III) that included cases of bullous vasculitis and Sweet syndrome. Among the three groups, the results of FS and of PS were discordant only in five cases (5/43, 11.6%). Compared to PS, FS had a sensitivity of 92.9% [95% confidence interval (95%CI) 64.17–99.63%] and a specificity of 100% in group I, sensitivity of 90.9% (95%CI 57.12–99.52%) and specificity of 100% in group II, and sensitivity of 83.33% (95%CI 60.78–94.16%) and specificity of 100% in group III. The degree of agreement between the results of the FS and of the PS was almost perfect (kappa = 0.95, 0.93 and 0.85 respectively).

Conclusions: This study suggests that FS is a valid approach for the rapid diagnosis of inflammatory dermatoses. This method is as specific as PS, although it is less sensitive.

For centuries skin pigmentation has played a major societal role. Genetic disorders of skin pigmentation have therefore always evoked the curiosity of both laypersons and physicians. Normal skin pigmentation is a complex process that begins with the synthesis of melanin within the melanocytes, followed by its transfer to neighboring keratinocytes where it is translocated to the upper pole of the nucleus and degraded as the keratinocyte undergoes terminal differentiation. Mutations in various genes involved in melanocyte migration during embryogenesis, melanin synthesis and melanosomal function and transfer have been shown to cause pigmentation disorders. In the present review, we discuss normal skin pigmentation and the genetic underpinning of selected disorders of hypo- and hyperpigmentation.