Itchy skin (pruritus) is a common symptom. It might seem it is related only to dermal issue, but it is not quite true. Itching can also be a symptom of systemic diseases.
The se fungal infectious diseases usually cause itching. When there are recurrent mycotic infections, it is always advisable to suspect an immunodeficiency. Immunocompromised patients such as people with AIDS, diabetics, or patients taking immunosuppressive drugs are more usually attacked by less common microorganisms including fungi. Even long-term use of antibiotics may be followed by recurrent skin fungal infections. Bacteria are weakened by antibiotics and that makes fungi organisms stronger. Skin mycoses occur more frequently in areas such as the groin, areas under the breasts and in skin folds in obese patients. In addition to itching the patients complain of skin redness and painful burning sensations. The therapy consists of adequate hygiene and application of antimycotic agents, usually in form of local ointments.
This is a chronic allergic skin disease that can be present at any age, but usually occurs in childhood and accompanies its victim to adulthood. The treatment is very difficult and mostly consists of a combination of local medication and lifestyle changes.
Urticaria is also an allergic skin disease, but this condition has more acute character. It occurs suddenly and quickly subsides as well. In addition to itching, there are also skin buds and reddish lesions.
Scabies is a relatively common parasitic infectious disease that is caused by a parasite called itch mite. Itch mites live in the skin and create subcutaneous tunnels, which causes itching sensations. More often affected body areas are skin between the fingers, wrists, penile foreskin, etc.
This viral infection is typical for childhood. The disease manifests as febrile state accompanied with itchy rash. Slightly more serious is the course of chickenpox in adults when it is very dangerous for pregnant women by possibility of serious fetal damage and tissue malformations.
Bile flow obstruction
If there is an obstruction in flow of bile such as gallstone obstruction, cancer narrowing biliary tree (gallbladder cancer, pancreatic cancer, biliary tree cancer), primary biliary cirrhosis or primary sclerosing cholangitis, bile begins to accumulate including substances dissolved in bile that would be otherwise excreted into the bowel. These substances include bilirubin (a bile pigment causing jaundice) and bile acids. Bile acids accumulate in the skin and cause unpleasant itchy sensations. If doctors manage to restore the bile outflow, both symptoms disappear.
Acute renal failure and advanced stages of chronic renal failure are related to inability to excrete metabolic waste products that start to accumulate in the organism. Especially the accumulation of urea causes skin itching.
Persistent skin itching is very unpleasant and some doctors even determine it as a subtype of pain. Scratching may help only for a short time, it irritates the skin and damages the skin cover, which helps bacterial microorganisms to penetrate the skin and cause secondary bacterial infection (secondary impetigo). Due to this complication it is reasonable not to scratch itchy areas, but it is often impossible to resist.
If the itching is accompanied by a rash, the best solution is to visit a dermatologist. When itchiness affects whole skin, or at least major part of body, or when it is accompanied by jaundice, it is wise to do some blood test, especially to estimate level of bilirubin, liver tests and renal parameters.
Treatment should be targeted against the causative disease (see relevant articles). Itching itself as a symptom may be suppressed by using some anti-allergy drugs, especially from group of antihistamines. They help to quell the inflammation and itching sensations, but usually cause drowsiness and sedation.