Dermatoses

(rashes, eruptions), a name embracing a variety of congenital and acquired skin pathologies.

Dermatoses may be the principal and often only symptom (or one of the symptoms) of a systemic disease (for example, measles , scarlet fever). They can develop as a result of external and internal irritations. External (exogenous) factors include mechanical irritants (bruises, friction, pressure), high and low temperatures (burns, frostbites), radiant energy (radioactive radiation, solar and other rays), chemical action (acids, alkalis, dyes), microorganisms (various cocci, parasitic fungi, spirochetes), insects (lice, mites, fleas), and plants (nettles). Internal (endogenous) factors include metabolic disturbances, endocrine activity, allergies, blood diseases, infectious diseases, and various intoxications. Dermatoses sometimes develop and are maintained by nervous or psychic trauma and mental or nervous exhaustion. Skin changes include discrete, sometimes confluent, spots, nodules, blisters, wheals , petechiae (minute hemorrhages), and pustules.