Arm,forearm All Morphologies

Specific conditions that tend to involve the Lower Arm

Annular   Granuloma annulare(elastolytic variant)

Annular Ridged   Disseminated superficial actinic porokeratoses

Excoriations   Neurotic excoriations,Prurigo nodularis

Linear   Plant allergic contact dermatitis,Lichen striatus,Lymphangitis from a distal source of infection

Nodules   Keratoacanthoma,Prurigo nodularis,Sporotrichoid spread of various infections including Aytypical Mycobacterium marinum,Sporotrichosis and Leishmaniasis

Papules   Eruptive syringomas,Lichen Myxedematosis(Lichen amyloid is usually on the legs),Papular urticaria,Polymorphous light eruption,Gianotti Crosti syndrome

Pigmented   Melanoma,Sun damage

Plaques   Sweet's syndrome,Erythema elevatum diutinum (elbows)

Pruritus   Brachioradial pruritus

Purpura   Solar or senile purpura

Red scaly   Tinea corporis,Nummular(Discoid) eczema,

Urticarial   Polymorphous light eruption(exclude lupus erythematosus)

Verrucous   Discoid hypertrophic lupus erythematosus,Keratoacanthoma,Squamous cell carcinoma,

White   Idiopathic guttate hypomelanosis,Stellate pseudoscars,Bier's spots(white avascular spots)

Modified from Regional Dermatology Gary M White