1.3 Papule

Papule.

Focal, elevated, solid, circumscribed, palpable increase in substance of skin, sharp borders, surface usually smooth.

Colors: if caused by inflammation, red; if secondary to other deposits: red, brown or yellow.

Size: ≤ 1 cm.

May appear on entire body, for example maculo-papular exanthem.

Papules may coalesce to form plaque.

Papule may enlarge to form nodule.

May develop scales, crusts or erosion.

May be associated with: macule (maculo-papular), vesicle (papulo-vesicular) or pustule (papulo-pustular).

Distinguish from nodule which is >0.5 cm.

Inflammatory papules often pruritic.

Multiple lesions: Drug exanthema, lichen planus, scabies, syphilis, acne.

Single lesions: Melanocytic nevus, tumors such as early nodular basal cell carcinoma.

Inflammatory infiltrate, deposits of lipids, proliferations of cells.