Red dots on the palms of the hands may be caused by eczema, atopic dermatitis, allergic purpura, insect bite dermatitis, hand-foot-mouth disease, vascular nevus, spider nevus and other diseases. 1. Eczema: The cause of eczema has not been fully clarified, and it is considered to be related to external stimuli, mental stress, heredity and other factors. It causes red papules and pimples with itching on the palms of the hands. 2. Allergic dermatitis: Allergic dermatitis is a broader concept that refers to a variety of skin inflammation. For example, contact with allergens leads to red spots with itching on the palms. 3. Anaphylactic purpura: Anaphylactic purpura is an allergic inflammation that may affect many small blood vessels throughout the body. It occurs in the palms of the hands, resulting in a localized red rash with an appearance similar to bleeding dots. 4. Insect bite dermatitis: Insect bite dermatitis is papular urticaria, which tends to occur in the hot summer months, such as mosquito bites resulting in localized red dots. 5. Hand, foot and mouth disease: Hand, foot and mouth disease is caused by enterovirus infections and is likely to occur in children under five years of age. Red dots may appear on the hands, feet, mouth or buttocks of affected children. 6. Vascular nevus: Vascular nevus is related to the proliferation of blood vessel network during embryonic period. It may appear on the body surface as dark red or burgundy color, slightly elevated or flat nodular thickened superfluous organisms. 7. Spider nevus: the cause of spider nevus is not clear, and it is considered to be related to the increase of androgen level. The diameter of spider nevus varies from a few millimeters to a few centimeters, and it may appear singly or more than one, resulting in the appearance of red dots on the palm of the hand. If red dots appear on the palms of the hands and persist, it is recommended to go to the dermatology department of the hospital to clarify the type of disease and target treatment.