Noneczematous Contact Dermatitis

IrritantIrritants and allergic contact dermatitisAllergic contact dermatitis usually presents as an eczematous process, clinically characterized by polymorphic lesions that vary according to the clinical phase, acute, subacute or chronic. Besides classic eczematous forms, however, different noneczematous clinical variants are possible. Of all the noneczematous variants, erythema multiforme-like contact dermatitisErythema multiforme-like contact dermatitis is the most common. Prevalently caused by woods, plantsPlants, and medicamentsMedicaments, the eruption presents with target-like, erythemato-vesicular, or urticarial lesions that may also extend to the whole cutaneous surface. The most frequent causative agents of purpuric contact dermatitisPurpuric contact dermatitis are rubberRubber, textilesTextiles, plantsPlants and others. The eruption presents with palpable purpuric elements that evolve slowly and are followed by a variably intense and persistent pigmentation. The histopathology shows the signs of leukocytoclastic vasculitis with erytrocytes extravasation. Lichenoid contact dermatitisLichenoid contact dermatitis is an uncommon form that presents with clinical features resembling those of lichen planus: papulous lesions featuring a peculiar lilac-red hue. Lyphomatoid contact dermatitisLyphomatoid contact dermatitis can be defined as a benign pseudolymphomatous allergic contact dermatitisAllergic contact dermatitis with clinical and histological features suggestive of cutaneous T cell lymphoma. It manifests with clinical features of plaque parapsoriasis. Pigmented contact dermatitisPigmented contact dermatitis is usually observed in dark phototypes with skin hyperpigmentationHyperpigmentation due to contact with azoic dyes. Chemical leukodermaChemical leukoderma, often clinically mimicking idiopathic vitiligo, is an acquired form of cutaneous pigment loss caused by exposure to a variety of melanocytotoxic chemicals. Dyshidrosiform contact dermatitisDyshidrosiform contact dermatitis can be primitive (expression of systemic contact dermatitisSystemic contact dermatitis) or secondary (a contact sensitivity which complicates a preexisting palmoplantar pompholyxPompholyx). Rare forms of noneczematous contact dermatitisNoneczematous contact dermatitis are also pustular contact dermatitisContact dermatitis and some nodular reactions.