Depigmentation from squaric acid dibutylester

Use of Contact Immunotherapy in the Treatment of Skin Diseases Other than Alopecia Areata

For decades, contact immunotherapy with dinitrochlorobenzene, diphencyprone, and squaric acid dibutylester has played an important role in both clinical practice and scientific research. It is listed as the first-line treatment for extensive alopecia areata and was more recently approved for melanoma treatment as an orphan drug in the USA. Moreover, owing to the relative low cost and safety, topical immunotherapy has also been used in many infectious, neoplastic, and inflammatory dermatological diseases. It is especially valuable in vulnerable groups, for cosmetic/pain sensitive areas, or for multiple lesions. In this review, we summarize the current evidence supporting the use of contact immunotherapy for treatment of skin diseases, from articles collected from PubMed database. Owing to space limitation and already numerous studies focusing on alopecia areata, we include only skin diseases other than alopecia areata. In addition to diseases that have been reported to be treated by contact immunotherapy, the hypothesized mechanism, prognosis prediction, efficacy, and safety of these topical agents are discussed.

Application of Topical Immunotherapy in the Treatment of Alopecia Areata: A Review and Update

Treatment of extensive or recalcitrant alopecia areata (AA) is a major clinical challenge. Even after thorough investigation of several medications, its treatment outcomes have remained unsatisfactory. While there is no US Food and Drug Administration-approved medication for AA yet, topical immunotherapy has been a well-documented treatment option. Dinitrochlorobenzene, squaric acid dibutylester, and diphenylcyclopropenone are three substances that have demonstrated efficacy in the treatment of extensive or recalcitrant AA. Despite being commonly used, the mechanism underlying topical immunotherapy is not well-elucidated and a wide range of clinical efficacies have been reported in the literature. The aim of this review was to summarize and update the pharmacology, mechanism of action, therapeutic efficacy, and tolerability of topical immunotherapy in the treatment of AA.

Goodbye warts, hello vitiligo: Candida antigen-induced depigmentation

Depigmentation after the use of topical immune modulators is a rare but reported event. Herein we present what is to our knowledge the first case of vitiligo at a site of Candida antigen injection.

The therapeutic use of topical contact sensitizers in benign dermatoses

Topical therapy using contact sensitizers has been practised since the 1960s to treat conditions associated with an altered immunological state. Dinitrochlorobenzene, squaric acid dibutyl ester and diphencyprone are most commonly employed in the therapy of alopecia areata and viral warts. Few dermatology departments in the U.K. provide such treatment. This systematic review discusses the various contact sensitizers used for topical immunotherapy, the methodology of treatment, factors influencing efficacy and likely adverse effects.

Efficacy of topical sensitizers in the treatment of alopecia areata

It has been more than 2 decades since the first report of the use of dinitrochlorobenzene to induce hair growth in 2 patients with alopecia areata. Other topical sensitizers, namely squaric acid dibutylester and diphenylcyclopropenone, have been used with variable success. This article reviews the efficacy and safety of the use of topical sensitizers in the treatment of alopecia areata.

Hypopigmentation in dogs treated with an inhibitor of platelet aggregation

Hypopigmentation was the principal manifestation of systemic toxicity when the experimental platelet aggregation inhibitor, PD-89454, was orally administered to Beagle dogs for 28 days. Pigmentation changes were present in skin of nose, lips and eyelids and mucosa of hard palate. Fontana-Masson stain demonstrated decreased melanin within melanocytes and keratinocytes. Melanocytes were globoid with inconspicuous dendritic processes and had small, incompletely pigmented melanosomes that were quantitatively reduced relative to controls. Toxic mechanism of action of PD-89454, structurally distinct from known depigmenting compounds, was not established but ultrastructural findings suggest an interference in melanosome formation and/or melanization.