Vitamin deficiency caused by toadflax disease (vitamin A deficiency disease), scrotal dermatitis and orchitis (riboflavin deficiency disease), accompanying lager (niacin deficiency disease) and scurvy (vitamin C deficiency disease) have skin and other manifestations, metabolic disorders amyloidosis, gout, lipoid deposition disease, calcium salt deposition disease can have metabolites deposited in the skin and elsewhere. Some metabolic diseases have cutaneous manifestations, for example, diabetic skin may have diabetic redness, diabetic gangrene or diabetic maculopathy. Another example is that patients with pancreatic hyperglycemia may have migratory necrotizing erythema.
(I) Endocrine disorders
Skin manifestations such as cranial gyrus occur when there is excessive secretion of growth hormone from the pituitary gland, and increased melanin in the skin when melanocyte-stimulating hormone is increased. In hyperadrenocorticism, Cushing’s syndrome is associated with swelling of the skin; in hypoadrenocorticism, Addison’s disease is associated with diffuse hyperpigmentation; thyrotoxicosis is associated with limited mucinous edema, while mucinous edema in hypothyroidism is associated with diffuse skin changes. Skin conditions such as menopausal keratosis and melasma are associated with sexual endocrinology.
(ii) Infections
Skin diseases such as urticaria, eczema, erythema multiforme and itchy skin can be associated with chronic foci of infection in the sinusitis or ear canal. Syphilis, tuberculosis and hare fever can invade both internal organs and skin, while actinomycosis, diphtheria and amoebiasis often spread from the body to the skin.
The rash of infectious diseases such as scarlet fever, smallpox, measles, rubella, chicken pox, etc. is of great diagnostic value. The rose rash of typhoid fever, the dark red spots and generalized petechiae of typhus, and the large petechiae of meningococcal meningitis also often help in the diagnosis. Other diseases such as sepsis may have erythema petechiae, influenza may have measles-like or scarlet fever-like erythema, rheumatic fever may have erythema multiforme or erythema nodosum, and wave fever may have erythema or purpura.
(C) Tumor
Nodular sclerosis invades brain tissue and may also cause skin changes. Neurofibromas can occur in the nerves, bone marrow and skin. Malignant tumors are often present within patients with dermatomyositis and acanthosis nigricans. The skin manifestations of the pigmented-polyposis syndrome are pigmented spots, while there are polyps in the intestinal wall.
(iv) Disorders of the nervous system
Leprosy and spinal cavitation have nerve damage with skin changes such as ulcers, dermatological pain, sensory abnormalities, sensory hypersensitivity, sensory insufficiency, hair-pulling fetish and nail biting fetish. Common skin diseases such as urticaria, hyperhidrosis, itchy skin, chronic lichen simplex, eczema and baldness occur, recurrence and aggravation can be related to emotions.
(E) Visceral diseases
Certain visceral diseases can have rashes, and sometimes the rash is a more significant or early symptom and facilitates the early detection of visceral diseases.
1. Liver.
The skin of patients with liver dysfunction may have dilated capillaries, diffuse pigmentation or specific purpuric lesions, axillary and pubic hair may be sparse, and nails may be grayish when blood albumin is low. Jaundiced patients often have itchy skin, cirrhotic patients may have palmar erythema or spider nevus, acute liver atrophy can cause skin bleeding.
Xanthomatosis and lid macular tumor can appear in patients with liver disease, delayed cutaneous porphyria patients often have abnormal liver function, bronze-colored skin hemochromatosis is often accompanied by cirrhosis.
2. Pancreas.
Within 1~2 days after the onset of acute pancreatitis, the skin may have pigment changes, subcutaneous bleeding at the umbilicus, and reticular cyanosis may occur in the lower extremities. Nodular fat necrosis may occur under the skin in patients with pancreatitis and pancreatic cancer, and migratory thrombophlebitis or annular erythema with superficial necrosis may occur in pancreatic cancer.
3.Renal.
The skin often has branched scales and may also be itchy when the kidney is not functioning well. In chronic nephritis patients with uremia, urate crystallizes on the skin surface and becomes frosty, and the skin may have papular erythema or blistering and bleeding.
Allergic purpura can be complicated by nephritis, to hemimelia is usually seen in patients with kidney disease who have increased non-protein nitrogen in the blood.
4. Gastrointestinal.
Urticaria, pellagra and allergic purpura are often associated with gastrointestinal symptoms, allergic vasculitis, connective tissue disease, thyrotoxicosis, mastocytic hyperplasia and carcinoid tumors may have both cutaneous and gastrointestinal symptoms, hemorrhagic hereditary capillary dilation and elastic fiber pseudoxanthoma have gastrointestinal bleeding, pigmented-polyp syndrome may have multiple polyps in the intestinal wall, enteropathic acromegaly Dermatitis and pellagra often have diarrhea.
In herpes-like dermatitis, the intestinal mucosa may have tissue changes similar to celiac disease, and in malignant atrophic papulosis, there may be scattered yellowish spots and small ulcers in the intestinal wall of the small intestine and even intestinal perforation.
Skin symptoms are often present in gastrointestinal disorders, the most common being urticaria. Malabsorption syndrome often has erythema or polymorphic erythema, and ulcerative colitis and restricted enteritis may be accompanied by gangrenous pyoderma.
5. Lung.
Chronic diseases may cause pestle finger, purpuric rash in tuberculosis, bronchial asthma is often complicated by eczema, urticaria or itchy rash, blood eosinophilia and lamellar infiltration of the lungs in Loeffler’s syndrome often have urticaria.