Rash

Introduction The spotted rash is large, red or purple, and the scent of the hand is called "spot". It is often caused by hot stagnation and stagnation. It is shaped like corn, red or purple, and is high above the skin. It is called "rash" (but it is not higher than the skin, and it does not interfere with the feeling of the hand). Stagnation, internal closed camp, from the blood to the skin. A macula is a simple change in skin color that can occur temporarily or persist. According to the color, erythema and other various pigment abnormalities can be distinguished.

Cause

First, microorganisms

(a) virus

1. Measles: caused by measles virus, transmitted by droplets through the respiratory tract and conjunctiva.

2. Rubella: caused by rubella virus, droplets are transmitted through the respiratory tract.

3. Childhood acute rash: recently demonstrated as human herpesvirus 6 (HHSV-6) infection, respiratory infection.

4. Infectious erythema: It has been confirmed to be human parvovirus B; (HPV-BI9) infection. Respiratory infection.

5. Echo virus rash: respiratory infection.

6. Infectious mononucleosis: caused by EB virus infection, droplet infection or direct contact.

7. Pityriasis rosea: In recent years, the research report has been caused by Coxsackie B virus. Contact infection.

8. Epidemic hemorrhagic fever: Infected by arboviruses. Rodents for the vector.

9. Atypical measles syndrome: measles virus infection. After more than ten years of vaccination against measles, the blood antibody decreased and re-infection caused the disease.

(two) bacterial infection

1. Scarlet fever: For type B hemolytic streptococcus infection, the toxin produced by bacteria causes symptoms of rash and poisoning.

2. Erysipelas: A group B type B hemolytic streptococcus is infected by skin damage, causing fever and local redness caused by bacterial toxins.

3. Erythrogenic dysentery: Infected by porcine bacillus, often infected by contact with pork, fish, and leather.

4. Staphylococcus aureus pharyngeal branch: The erythema toxin produced by the exotoxin of the bacterium causes a scarlet fever-like rash.

5. Streptococcus A angina: A fever caused by the toxin of the bacterium and measles-type erythema.

6. Soft tissue traumatic infectious scarlet fever: more common with Staphylococcus aureus.

7. Typhoid fever: the pathogen is Gram-negative typhoid. Digestive tract infection, rose rash is formed by bacteremia.

8. Undetermined leprosy and tuberculosis-like leprosy: caused by Mycobacterium leprae, positive for acid-fast staining. The bacteria naturally dried for 7 days. Tumor-type sputum or membrane secretions have 200 million bacilli per day as the main source of infection.

(c) spirochete infection

1. Secondary syphilis: Infected by Treponema pallidum. Mainly due to unclean sexual contact, blood transfusion, fetal transmission, organ transplantation. Causes bacteremia to spread the whole body organs.

2. Lyme's disease: Infected by a bite of Borrelia burgdorferi, causing migratory erythema in the bite.

(4) Old gram-infected infection: causing epidemic typhus. Infected by sputum as a vector.

(5) Chlamydia: It is transmitted to the human by the bird's parrot, and the parrot fever occurs.

Second, physical factors

(1) Fire-induced erythema: caused by vasodilatation and hyperemia caused by fire, hot compress and infrared radiation for a long time.

(B) frostbite erythema: long-term cold small arteries contraction, long-term vascular palsy and expansion, venous congestion, local blood circulation is poor, purple-red water erythema occurs.

(3) Phototoxic erythema: It is a strong sunlight. Longer time, causing skin damage erythema.

(4) Photoallergic erythema: contact with asphalt, coal tar, or light-sensitive drugs such as sulfonamides, tetracycline, etc. Allergic erythema is produced by sunlight.

(5) Plant solar erythema: It is also photoallergic.

(6) Photo-linear reticulocyte hyperplasia: caused by allergies to visible light and ultraviolet rays.

(7) Diaper dermatitis: Local erythema occurs due to the diaper's damp heat decomposing urine to produce ammonia.

Third, allergic

(A) drug-induced erythematous rash: mostly an allergic mechanism. Among them, type I delayed type of blood type immune complex is more common. Such as measles-type drug eruption, erythroderma, contact dermatitis, and eczema-type drug eruption are more common. The drug has a small molecular weight and is a hapten, which must be combined with tissue proteins in the body to form a complete antigen. A hapten drug makes the conjugate specific, while a tissue protein makes the conjugate antigenic.

1. Fixed erythema drug eruption: caused by sulfonamides, antipyretic and analgesic drugs, such as somi pain, painkillers, and tetracycline.

2. Measles-like and scarlet-like fever-like drug eruption: is a delayed type of allergic reaction, ampicillin, sulfonamides, antipyretic analgesics, penicillin is more common.

3. The erythrodermic drug eruption can be caused by aggravation of measles, or sudden onset.

4. Facial butterfly lupus-like syndrome: more common in elderly patients. Often caused by dysfunction, penicillamine, phenytoin, ketone, procaine phenolamine.

5. Polymorphic erythema type drug eruption: common drugs are sulfonamides.

(2) Other skin allergic diseases

1. Allergic sub-septic erythema: may be associated with streptococcus, staphylococcus, tetanus serum, and pollen.

2. Disseminated eosinophilic collagen disease: may be type-allergic. Often associated with atopic dermatitis, asthma.

3. Seasonal contact facial dermatitis: allergic to pollen.

4. Contact dermatitis: a delayed allergic reaction to type IV.

5. Facial recurrent dermatitis: may be associated with cosmetic and autonomic disorders.

Fourth, animal insects

(1) Filaria: larvae lower leg erysipelas dermatitis mosquito bite infection.

(2) rash-like erythema: caused by maggots, larvae and their larvae.

(3) Insect erythema erythema: common are pine caterpillars, mulberry caterpillars, stag beetles, and caterpillars.

(4) Sea dermatitis: The tentacles and sea thorns of sea otters contain sea scorpion toxins, which contain serious proteins and peptides.

(5) Rice field dermatitis: Itching of the skin of the schistosomiasis into the human skin.

(6) Venomous snake bites: Venomous venomous venomous venom contains neurotoxins and circulating toxins causing movement disorders, difficulty swallowing, respiratory paralysis; circulating toxins manifest as bleeding, heart failure and death.

5. Autoimmune

(1) Lupus: At present, autoimmunity is the main mechanism. But genetic factors. Sunlight, estrogen, and viral infections also have a certain relationship.

(B) juvenile rheumatoid arthritis.

(C) Behcet syndrome: polymorphic erythema can occur.

Six, congenital hereditary

(1) Toxic erythema in newborns.

(2) Congenital ichthyosis erythroderma: an autosomal recessive hereditary disease.

Seven, the reason is unknown

(1) Simple annular erythema.

(2) Limotic ring erythema.

(3) Telecentric annular erythema.

(D) persistent pigment abnormal erythema.

Eight, metabolic and nutritional disorders

(A) desquamative erythroderma: also known as leiner disease. Most occur in breastfed babies, often within 10 months. In the absence of vitamin B group and vitamin H.

(B) Bud spot: caused by vitamin A deficiency.

(3) Pellagra: It is caused by niacin deficiency and sun exposure, causing brownish red rough keratinized spots on the back of the hands and feet, and the boundary is clear.

Nine, tumor

(A) carcinoid syndrome: due to carcinoid production of the peptide hormone serotonin, causing paroxysmal facial, neck, chest large erythema.

(B) glucagonoma syndrome: recurrent necrotic erythema can occur.

Ten, other

Palm erythema: occurs in the palm-sized fish, is red and red erythema, often combined with spider disease, is a complication of visceral disease or skin disease. Found in pregnancy, liver disease, rheumatoid, hereditary hand and foot hyperhidrosis, hair red pityriasis, psoriasis and eczema.

an examination

Related inspection

Serum globulin (G, GL0) skin smear microscopy

First, medical history

The medical history should include age, gender, occupation, place of origin, race, marital status, etc.

(1) Current medical history

The time of onset of the disease, the initial symptoms, the location and sequence, the development, the presence or absence of remission, possible causes, internal and external causes. Treatment status and response and effect, disease period.

(2) Past history, family history, personal history

The medical history is a detailed investigation of the patient's illness at the time and all relevant conditions before and after the illness. For measles, the boy is 3 years old and has a spring incidence. He has the same disease in kindergarten. At the beginning of the onset, there was a high fever. On the third day, there was a white spot on the lateral buccal membrane of the second molar, accompanied by conjunctival and nasal membrane catarrh and cough. After the fourth day, the hair was developed in the posterior, hair, and face, and the neck and upper limbs were reported to be dry and the lower limbs were dense red rash. After 2-5d rash, the whole course of disease is about 2 weeks. The above medical history is a more comprehensive history of measles. Therefore, detailed medical history is a prerequisite for diagnosing the disease. If you look at the age, in general, infants and children, if you have burned first, then there is a rash in the body, you should first consider viral diseases. Such as measles, children with acute rash, rubella and other diseases. Such as young women, facial butterfly erythema, fever, joint pain, should first consider systemic lupus erythematosus. If elderly patients have brown rash on the face and forearm and are asymptomatic, they should be considered as seborrheic keratosis. It can be seen that age, gender, skin lesion characteristics and location, whether it is fever, whether it is epidemic, the relationship between rash and fever, has its special diagnostic significance.

Second, physical examination

Taking a medical history gives us a first impression and revelation, and also guides us to a concept of the nature of the disease.

(1) Visual inspection

The light must be good, and the whole body skin and tympanic membrane should be observed. Note on the diagnosis:

1. The form of damage: whether it is unitary or polymorphic.

2. Distribution: whether it is systemic symmetry, or localized asymmetry; whether it is stretching or flexing; distributing those special parts; whether it is densely distributed or scattered; it is strip-like, band-like or distributed along the nerve; At the exposed part, or at the covered part.

3. Specific skin lesion characteristics: including size, color, shape, smooth or rough surface, scale characteristics, skin characteristics, whether there is erosion, exudation, ulceration, etc.

4. Be sure to observe the damage of the membrane, tongue, and genital membrane. Because many diseases have special damage on the facial membrane, such as palmar purulent psoriasis often accompanied by gully tongue. Secondary syphilis is often accompanied by oral plaques.

(2) Plague and palpation

1. Diagnosing

If the spotted rash is red inflammatory congestive, the pressure will fade; if the vasculitic plaque is hemorrhagic, the pressure will not fade. Such as allergic purple epilepsy.

2. Palpation

Can understand local tenderness, temperature and height. Such as erysipelas, there is tenderness and local temperature rise. These two characteristics are often purulent infectious diseases. It can also test for paresthesias, such as leprosy patients.

Combining medical history with physical examination can further summarize the more favorable diagnostic basis. For example: If the patient is male, 20 years old, there is a systemic distribution of rose rash, no symptoms, and there is a round rash in the heart of the hands and feet, and the lymph nodes in the whole body should be considered as a secondary syphilis rash. Therefore, patients should be asked whether there is a history of sexual disorder, if any, should be done syphilis serum test, the USR titer is higher than 1:16; the diagnosis can be established. One patient is 30 years old. The chief complaint has been itchy on the sides of the neck, the ankle, the elbow fossa and the elbow fossa for several years. After long-term scratching, the local skin becomes thicker, and flat polyhedral skin lesions appear. The skin texture is clear and the moss is Xuehua. Sexual dermatitis. If the degree of loss is an itchy erythema on the wrist, it should be considered contact dermatitis caused by the strap. And for local factors. A patient develops scaly erythema on the head, back, and extremities at the age of 20 years. It is a typical psoriasis patient after micro-itching to remove the mica-like white shavings, grabbing all the debris to expose a smooth red film, and having a large bleeding point at the tip of the needle. It is often the case that people with medical history often have this history.

Third, laboratory inspection

Laboratory examinations must be summarized and analyzed based on objective data learned from medical history and physical examination, from which several diagnostic possibilities may be proposed, and further consideration should be given to those examinations to confirm the diagnosis. Therefore, laboratory tests should be clearly targeted and targeted, not blind. A hierarchical analysis and judgment is the correct way of thinking, which is a rigorous scientific attitude and diagnostic thinking. Only then can we improve ourselves through serious practice. At the same time, it is also necessary to improve the correct diagnosis rate.

Fourth, equipment inspection

Some skin diseases can be seen with a magnifying glass to check the characteristics of the lesions. Use the Wood light to check for jaundice and white sputum. Dark green and bright green fluorescence can appear in the dark room. During the inspection, the batch of substances, such as the urine and feces of the delayed skin lining, were mostly reddish and red. Capillary fluoroscopy is used to observe the capillary capillaries for psoriasis, hardness disease, dermatomyositis and the like. Use a pure knife to scrape the nasal new membrane of the tumor type leprosy to make a smear, and do acid-resistant staining to check the leprosy.

Fifth, skin tissue pathology

Dermatology skin tissue pathology, its independence and particularity. Skin histopathology focuses on the epidermis, dermis, subcutaneous tissue, and skin appendages. Skin lesions are mostly exposed, have different forms, and are obvious to the clinic. Combine clinical signs and pathology, especially to observe changes in different stages of the disease, to understand its dynamics. This is important for diagnosing skin diseases. Pathological examination of skin diseases is generally used to diagnose granulomatous diseases such as skin tumors, large cancerous skin diseases, allergic vasculitis, leprosy, tuberculosis, deep mycosis, syphilis, and connective tissue diseases. Flat lichen, psoriasis, etc. have a high diagnostic value. Combined with histochemistry and special staining, the diagnostic accuracy can be improved.

In recent years, biochemistry, immunofluorescence technology, immunolabeling technology, PCR test, etc. Research on the pathogenesis of the skin is of great significance.

Differential diagnosis

The diagnosis should be differentiated from the following symptoms:

1. Exile heat:

The body temperature is constant at a level of 39 to 40 degrees Celsius, for several days or weeks, and the temperature fluctuation range of less than 1 degree Celsius within 24 small events is called the heat of detention! It is common in large leaf pneumonia and typhus.

2. erythema scales:

Scales are cuticles of the epidermis that are about to fall off or have fallen off. Its size, shape, thickness, quantity, color are different, some are dry, some are greasy. Most are secondary damage to skin diseases with erythema or papule damage. Erythema is a local or systemic red spotted rash that is localized or systemicly dilated by the dermal papillary capillary network. Psoriasis, seborrheic dermatitis, pityriasis rosea, parapsoriasis, discoid lupus erythematosus and other diseases can be expressed as erythema scales.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.