A red rash refers to the appearance of small red bumps on the surface of the skin.

In ancient times, it was called "zhen". Suwen . Zhizhenyao Da Lun states: "...Shaoyin celestial control, when the guest prevails, then a red rash will appear externally." Yizhen Yide refers to it as "epidemic eruptive disease". Yishacao calls it "scarlatina". Some medical texts discuss macula and papule together, or use the term "macula" to encompass "rash". However, macula and rash are not the same (for detailed differentiation, see the entry on macula). Rash should also be differentiated from "pox" and "scarlatina": 1. "Pox" mostly occurs in children, initially presenting as red papules, which within a few hours develop into millet or bean-sized round blisters surrounded by a red halo, filled with serous fluid that turns from clear to turbid; rash does not involve blisters or fluid filling. 2. "Scarlatina" involves sore throat, fever, and faint scarlet spots all over the body that gradually become widespread and merge into patches, with no normal skin between the spots, pale area around the mouth, and a tongue resembling Chinese wax myrtle bark, which is different from a rash.

This article only discusses red rashes caused by internal diseases.

bubble_chart Pattern Analysis

1. Heat Entering the Nutrient-Blood Level︰It is often accompanied by persistent high fever, with red or dark purple petechiae appearing on the trunk or limbs. These petechiae do not fade under pressure, are not raised to the touch, and normal skin can be seen between the spots. It may also involve dysphoria, delirious speech, or complications such as convulsions. The tongue texture is crimson, the tongue coating is yellow, and the pulse is rapid or thin and rapid. This condition is caused by the inward invasion of warm-heat pathogens into the nutrient-blood level, occurring during the course of warm disease. The warm-heat pathogens invade the nutrient-blood level, damaging the blood collaterals and causing external leakage, resulting in the eruption. Key diagnostic points include petechiae that do not protrude above the skin, accompanied by high fever, dysphoria, delirious speech, convulsive syncope, and a crimson tongue texture. Treatment should focus on clearing the nutrient aspect, cooling the blood, and removing toxins. The recommended formulas are Plague-Clear Toxin-Vanquishing Decoction or Nutrient-Clearing Decoction.
2. Wind-heat with Dampness︰The onset is relatively acute, with red or pale red granular papules of varying shapes and sizes. In densely affected areas, they may merge into patches, accompanied by cutaneous pruritus or intense itching. Associated symptoms include fever, chest tightness, dysphoria, scanty and dark urine, a crimson tongue texture, a yellow and greasy tongue coating, and a floating, rapid pulse. This is due to wind-heat combined with dampness obstructing the striae and interstice. It is often caused by summerheat invasion compounded by cold-dampness, where summerheat is constrained by cold-dampness, leading to heat stagnation and dampness retention, which stagnates in the striae and interstice, resulting in a rash resembling chestnut granules that protrude from the skin, are tightly rooted, and unbearably itchy. Accompanying symptoms include chest and gastric stuffiness, a sticky mouth without thirst, and dysphoria. Treatment should focus on dispersing wind and clearing heat, as well as draining dampness. The recommended formula is Wind-Dispersing Powder with modifications.
3. Wind-cold Depression︰The onset is sudden, with pale red rashes that worsen upon exposure to wind and cold, cutaneous pruritus, appearing intermittently in varying sizes and shapes, accompanied by fever, aversion to wind, headache, floating pulse, and other symptoms. It occurs when sweating exposes one to wind or when wind-cold is sensed after bathing, stagnating in the nutrient-defense system and clashing with qi and blood, manifesting as rashes on the skin. The red rashes come and go, worsening with wind and cold, accompanied by cutaneous pruritus, or symptoms such as body heat and aversion to wind. Treatment should focus on dispelling wind, dispersing cold, and promoting eruption. The recommended formula is Schizonepeta and Saposhnikovia Toxin-Vanquishing Powder with modifications.
4. Blood Deficiency︰The rash appears pale red or pallid, with varying sizes from millet grains to broad bean segments, unevenly distributed, recurring intermittently, appearing and disappearing, often worsening at night and persisting for years. Symptoms include dizziness, restlessness, a dull complexion, a pale tongue texture, and a thin, weak pulse. This condition arises from insufficient nutrient-blood and weakened defensive qi at the surface, allowing wind pathogens to invade the skin and disrupt the nutrient-defense mechanism internally, leading to the rash. The clinical features include recurrent eruptions that come and go, persisting for years, accompanied by dizziness, palpitations, a pale tongue, and a thin pulse. Treatment should focus on nourishing blood and dispelling wind. As ancient physicians stated, "To treat wind, first treat blood; when blood circulates, wind dissipates on its own." The recommended formula is Angelica Decoction.

bubble_chart Documentation

1. "External Contraction Warm Heat Chapter": "If there are macules and papules, they are all manifestations of different pathogenic factors, each discharging according to its own region. However, macules are mostly related to blood, and papules are often related to qi. Both macula and papule are signs of pathogenic qi being exposed. When they appear, the spirit should be clear and refreshed, indicating the resolution of external factors and harmony within. If macules and papules appear and the person becomes unconscious, it means the healthy qi cannot overcome the pathogenic qi, leading to inward invasion, or it may be due to the depletion of stomach fluid."
2. "Chinese Medicine Clinical Essentials": "In warm febrile diseases, if the body heat persists and small red spots appear, they are called 'papules,' which have the same cause as macules. However, macules are more severe, while papules are slightly milder. Macules are deeper in the muscles, while papules are more superficial in the blood vessels. Although they can appear simultaneously, they should not be confused as the same."