The most common form of cutaneous mastocytosis (MASTOCYTOSIS, CUTANEOUS) that occurs primarily in children. It is characterized by the multiple small reddish-brown pigmented pruritic macules and papules.

A vascular reaction of the skin characterized by erythema and wheal formation due to localized increase of vascular permeability. The causative mechanism may be allergy, infection, or stress.

Skin lesions due to abnormal infiltration of MAST CELLS. Cutaneous mastocytosis is confined to the skin without the involvement of other tissues or organs, and is mostly found in children. The three major variants are: URTICARIA PIGMENTOSA; diffuse cutaneous mastocytosis; and SOLITARY MASTOCYTOMA OF SKIN.

A heterogenous group of disorders characterized by the abnormal increase of MAST CELLS in only the skin (MASTOCYTOSIS, CUTANEOUS), in extracutaneous tissues involving multiple organs (MASTOCYTOSIS, SYSTEMIC), or in solid tumors (MASTOCYTOMA).

Hereditary, progressive degeneration of the neuroepithelium of the retina characterized by night blindness and progressive contraction of the visual field.