Christopher B. Zachary

Oral allergy syndrome (OAS): symptoms of IgE‐mediated hypersensitivity to foods

Eighty highly atopic patients were selected for study because they had either atopic eczema (fifty cases) or atopic reactivity to foods, as judged by a positive skin‐prick test (thirty cases). In all, sixty‐five out of eighty subjects (81%) described symptoms of some kind provoked by foods, but correspondingly positive skin tests were found in only half of these, thirty‐three out of eighty (41%). The symptoms experienced by thirty‐one of the thirty‐three patients with positive skin tests were immediate in onset (within 1 hr) and were at first confined to the upper gastrointestinal tract, the most frequent symptoms being oral irritation and throat tightness. In a proportion of these patients, further symptoms such as urticaria, asthma or anaphylaxis developed following the initial oral symptoms, which suggested the term‘oral allergy syndrome’. In the absence of the oral allergy, symptoms such as asthma, urticaria, migraine or eczema starting later than 1 hr after food were seldom associated with positive skin tests. In the oral allergy syndrome, the characteristic symptoms (strong association with positive skin tests and RAST, time of onset and sites at which symptoms are expressed) suggest a causative relationship between exposure to food antigens and specific IgE‐induced release of mediators. In cases of food intolerance that lack a characteristic symptom pattern and a positive skin test or radio‐allergo‐sorbent test, it seems appropriate to consider non‐IgE‐mediated causes.

A role of PDGFRα in basal cell carcinoma proliferation

Activation of the hedgehog pathway, through the loss of patched (PTC) or the activation of smoothened (SMO), occurs frequently in basal cell carcinoma (BCC), the most common human cancer. However, the molecular basis of this neoplastic effect is not understood. The downstream molecule Gli1 is known to mediate the biological effect of the pathway and is itself up-regulated in all BCCs. Gli1 can drive the production of BCCs in the mouse when overexpressed in the epidermis. Here we show that Gli1 can activate platelet-derived growth factor receptor α (PDGFRα) in C3H10T½ cells. Functional up-regulation of PDGFRα by Gli1 is accompanied by activation of the ras-ERK pathway, a pathway associated with cell proliferation. The relevance of this mechanism in vivo is supported by a high level expression of PDGFRα in BCCs of mice and humans. In the murine BCC cell line ASZ001, in which both copies of the PTC gene are inactivated, DNA synthesis and cell proliferation can be slowed by re-expression of PTC, which down-regulates PDGFRα expression, or by downstream inhibition of PDGFRα with neutralizing antibodies. Therefore, we conclude that increased expression of PDGFRα may be an important mechanism by which mutations in the hedgehog pathway cause BCCs.

In situ quantification of T‐lymphocyte subsets and Langerhans cells in the inflammatory infiltrate of atopic eczema

Tissue from the acute, non‐infected eruption of sixteen atopic eczema subjects was subjected to an indirect immunoperoxidase technique using monoclonal antibodies recognizing T‐lympho‐cyte subsets, Langerhans cells and natural killer cells. Over half the cells infiltrating the dermis were T lymphocytes, including a large majority of helper T cells and relatively few suppressor T cells. Langerhans cells were present in significant proportions in the dermis and probably reflected increased antigen presentation within the affected skin. There was no evidence of increased natural killer cell presence.

Complications of fractional CO2 laser resurfacing: Four cases

Fractional ablative laser therapy is a new modality which will likely be widely used due to its efficacy and limited side‐effect profile. It is critical to recognize, characterize, and report complications in order to acknowledge the limits of therapeutic efficacy and to improve the safety of these devices.

Modulating the Er:YAG laser

In the past 2 years, there has been some controversy about the optimal laser system, or combination of systems, for cutaneous resurfacing. Initially, it seemed that the Er:YAG laser would have significant advantages over the CO2 laser. In practice, some of those who jumped early onto the Er:YAG bandwagon have been unimpressed with the degree of skin tightening that can be achieved with this system. Also, the excessive bleeding induced by the Er:YAG lasers prevented deeper vaporization. During the past 18 months, three new “modulated” Er:YAG lasers have been produced that are said to be able to achieve CO2 laser‐like effects, while maintaining the Er:YAG laser advantages. The purpose of this article is to examine these new systems and to discuss their potential benefits, if any, over the “conventional” Er:YAG lasers, and the CO2 lasers.

The pathogenesis of amiodarone‐induced pigmentation and photosensitivity

A new method has been used to measure tissue levels of amiodarone and its major metabolite desethylamiodarone. Amiodarone‐pigmented skin has a drug and metabolite concentration ten times that of non‐pigmented skin. Iodine‐rich amiodarone and its metabolite have been detected in secondary lysosomes by energy dispersive analysis of X‐rays. Amiodarone induces a phototoxic reaction with an action spectrum in both the UV‐B and UV‐A wavelengths.

Evaluation of a novel fractional resurfacing device for treatment of acne scarring

Pulsed carbon dioxide (CO2) laser devices are considered highly effective treatment options for skin resurfacing. However, the high risk for significant treatment complications following CO2 resurfacing has warranted the development of new treatment modalities. The concept of fractional photothermolysis was developed to address the shortcomings of ablative and non‐ablative device modalities. This report evaluates a fractional approach to CO2 laser resurfacing for the treatment of moderate to severe acne scarring. The primary endpoint of the study was the overall improvement in the appearance of acne scarring.

Fractional Deep Dermal Ablation Induces Tissue Tightening

Due to the significant risk profile associated with traditional ablative resurfacing, a safer and less invasive treatment approach known as fractional deep dermal ablation (FDDA™) was recently developed. We report the results of the first clinical investigation of this modality for treatment of photodamaged skin.

Quantitative analysis of T‐lymphocyte subsets in atopic eczema, using monoclonal antibodies and flow cytoafluorimetry

An analysis of T‐lymphocyte subpopulations was performed on thirty‐eight consecutive patients with atopic eczema, using monoclonal antibodies and flow cytofluorimetry. The total T‐lymphocyte and helper T‐cell numbers did not differ significantly from those of a matched control group, but there was a highly significant reduction in suppressor T‐cell numbers among the atopic group. Both suppressor T‐cell deficiency and circulating IgE elevation were found to correlate positively with disease activity.

Outcome of carbon dioxide laser therapy for persistent cutaneous viral warts

Twenty‐two adults with persistent, symptomatic viral warts on the hands or feet which had failed to respond to conventional therapy were treated by carbon dioxide (CO2) laser ablation under local anaesthesia. Four patients did not return for follow‐up treatment. Of the remaining 18 patients, 12 had plantar warts, the other six had warts on the hands that were mainly periungual. The median duration of the warts prior to laser treatment was 5 years. The areas treated were solitary in eight and multiple in 10 cases. After an average follow‐up period of 10 months (minimum 6 months), all of the treated areas were clear of warts in 10 patients (56%), some had cleared in three, and all the treated warts had relapsed in the other five patients. Side‐effects were commonly observed, especially post‐operative pain, temporary loss of function of the treated part and scarring. The use of the CO2 laser may clear otherwise resistant viral warts but a significant morbidity may occur with this method of treatment.