A petechial rash is a skin lesion that can take on a variety of forms, from a simple change in skin color to a raised skin surface or blisters. To treat this disease, we must also look at what are the main causes of the rash with petechiae. The causes of the rash with petechiae are as follows: 1. Acute rash infectious diseases Acute rash infectious diseases include scarlet fever, rubella, chicken pox, measles, dengue typhus, tsutsugamushi, typhoid fever, paratyphoid fever, dengue fever, hare fever, horse nose gangrene and many other diseases. It is characterized by a rash mostly accompanied by different forms of fever. Due to the different types of diseases, such diseases have their own characteristics. 2. Connective tissue diseases are mainly seen in acute disseminated lupus erythematosus. Its typical skin damage is butterfly-shaped erythema on the nose or cheeks, and other skin damage such as exudative pleomorphic erythema, papules, purpura, urticaria, etc., accompanied by fever, rash splenomegaly, arthralgia and other symptoms: laboratory tests can reveal accelerated blood sedimentation, decreased serum protein, positive antinuclear antibody test, and the discovery of lupus cells is decisive for confirming the diagnosis of this disease. 3. Allergic and allergic diseases Such as rheumatic fever, 1/3 of the patients may have various rashes in the form of petechiae. The most common ones are annular erythema and subcutaneous nodules, which are often accompanied by fever, sweating, joint pain and accelerated blood sedimentation. Drug fever is usually accompanied by a drug rash, but it is symmetrically distributed and polymorphic, often with a spasmodic, itchy, burning sensation. The common types of rash are scarlet fever-like erythema, urticaria, measles-like erythema, and fixed erythema, which are preceded by a history of taking antimicrobials, salicylic acid preparations, luminal, etc.