Non-eczematous pigmented interface dermatitis from para-tertiary-butylphenol-formaldehyde resin in a watchstrap adhesive

Pigmented contact dermatitis: A brief review

Hyperpigmentation is one of the common pigmentary complaints that brings the patient to dermatology services. Though there are multiple etiologies for hyperpigmentation, pigmented contact dermatitis (PCD) remains a common diagnosis. The cosmetics containing dyes, preservatives, fragrances, bactericidal, emulsifiers/surfactants, and vehicles are the potential sources, and paraphenylenediamine, benzyl salicylate, brilliant lake red R, thiomersal and gallate mix are some of the most commonly implicated allergens.

The clinical manifestation includes diffuse or patchy brown to blue-black pigmentation of the cheeks, the outer surface of ears, preauricular region, temporal area, nape of the neck, and upper back. Patch testing plays a pivotal role in the diagnosis of PCD and the testing series has to be selected according to the representative population. Given the chronicity of the disease, counseling patients against the use of cosmetics is challenging as the pigmentation tends to persist for longer durations inspite of stopping cosmetics. The pillars of treatment in PCD include recognition of the culprit allergen and preventing further exposure along with pharmacological therapy. This review provides a brief overview and an insight into the etiopathogenesis and management of PCD.

Hand dermatitis: uncommon presentations

Hand dermatitis is a common diagnosis seen in dermatologic and general practice. It can present with typical morphology, but uncommon manifestations are possible. This review reports on common and uncommon presentations of irritant and allergic hand dermatitis focusing on uncommon localizations, time course, and morphology such as follicular, pustular, bullous, ulcerous, exudative erythema multiforme-like, purpuric, lichenoid, pigmented, and depigmented skin lesions. Clinical diagnosis can be challenging. Even histopathology is not always very helpful. Thorough evaluation of the patient's history and investigation of clinical morphology are the cornerstones of diagnosis.