question: Why is that when my skin gets hot (in the sun, warm shower, exc.) I start to feel itchy?
comment: As far as I know, hot water and sun on your skin dries it out. Anything hot will pull moisture from your skin to the surface, and dry skin is typically what causes the itchiness. If you're looking for a solution, use moisturizer on your skin after you shower and make sure to wear appropriate strength sunblock when out in the sun!
passages: The condition manifests as an allergic-like reaction, causing a warm red wheal to appear on the skin. As it is often the result of scratches, involving contact with other materials, it can be confused with an allergic reaction, when in fact it is the act of being scratched that causes a wheal to appear. These wheals are a subset of urticaria (hives), and appear within minutes, in some cases accompanied by itching. The first outbreak of urticaria can lead to other reactions on body parts not directly stimulated, scraped, or scratched. In a normal case, the swelling will decrease without treatment within 15–30 minutes, but, in extreme cases, itchy red welts may last anywhere from a few hours to days.
   Section::::Signs and symptoms.:Dermatitis.
  
  The first potential reaction is an itchy, papular rash that results from cercariae penetrating the skin, often in a person's first infection. The round bumps are usually one to three centimeters across. Because people living in affected areas have often been repeatedly exposed, acute reactions are more common in tourists and migrants. The rash can occur between the first few hours and a week after exposure and lasts for several days. A similar, more severe reaction called "swimmer's itch" reaction can also be caused by cercariae from animal trematodes that often infect birds.
  
  Section::::Signs and symptoms.:Katayama fever.
   BULLET::::- Xerosis – dry skin, the most common cause, frequently seen in the winter and also associated with older age, frequent bathing in hot showers or baths, and high-temperature and low-humidity environments
  
  Section::::Causes.:Other medical disorders.
  
  BULLET::::- Diabetes mellitus, a group of metabolic diseases in which a person has high blood sugar
  
  BULLET::::- Hyperparathyroidism, overactivity of the parathyroid glands resulting in excess production of parathyroid hormone (PTH)
  
  BULLET::::- Iron deficiency anemia, a common anemia (low red blood cell or hemoglobin levels)
  
  BULLET::::- Jaundice and cholestasis – bilirubin is a skin irritant at high concentrations
   Section::::Interactions with humans.
  
  Section::::Interactions with humans.:Dermatitis.
  
  The small eggar is covered in setae, which can cause dermatitis in humans upon contact. These tiny hairs have a tube-like structure that becomes embedded in exposed skin, delivering a chemical irritant. Reactions vary in severity, but typically present as an itchy rash that spreads from the area of contact and can develop red bumps and papules. The rash usually clears up after about a week.
   BULLET::::- Itchy, burning skin. Irritant contact dermatitis tends to be more painful than itchy, while allergic contact dermatitis often itches.
  
  While either form of contact dermatitis can affect any part of the body, irritant contact dermatitis often affects the hands, which have been exposed by resting in or dipping into a container (sink, pail, tub, swimming pools with high chlorine) containing the irritant.
  
  Section::::Causes.
   After the exposure, skin may turn red in as little as 30 minutes but most often takes 2 to 6 hours. Pain is usually strongest 6 to 48 hours after exposure. The burn continues to develop for 1 to 3 days, occasionally followed by peeling skin in 3 to 8 days. Some peeling and itching may continue for several weeks.
  
  Section::::Signs and symptoms.:Skin cancer.
   The rash takes one to two weeks to run its course and may cause scars, depending on the severity of the exposure. Severe cases involve small (1–2 mm), clear, fluid-filled blisters on the skin. Pus-filled vesicles containing a whitish fluid may indicate an infection. Most poison ivy rashes, without infections, will resolve within 14 days without treatment. Excessive scratching may result in infection, commonly by staphylococcal and streptococcal species; these may require antibiotics.
  
  Section::::Cause.
   Atopic dermatitis is an allergic disease believed to have a hereditary component and often runs in families whose members have asthma. Itchy rash is particularly noticeable on head and scalp, neck, inside of elbows, behind knees, and buttocks. It is very common in developed countries, and rising. Irritant contact dermatitis is sometimes misdiagnosed as atopic dermatitis. Stress can cause an atopic dermatitis to worsen.
  
  Section::::Diagnosis.:Common types.:Contact.
   A complete patient history combined with negative allergic patch testing is usually necessary to reach a correct diagnosis. The simplest form of physical irritant contact dermatitis results from prolonged rubbing, although the diversity of implicated irritants is far wider. Examples include paper friction, fiberglass, and scratchy clothing.
  
  Section::::Physical irritant contact dermatitis.:Low humidity.
   BULLET::::- Phytophotodermatitis: UV radiation induces inflammation of the skin after contact with certain plants (including limes, celery, and meadow grass). Causes pain, redness, and blistering of the skin in the distribution of plant exposure.
  
  BULLET::::- Polymorphic light eruption: Recurrent abnormal reaction to UVR. It can present in various ways including pink-to-red bumps, blisters, plaques and urticaria.
  
  BULLET::::- Solar urticaria: UVR-induced wheals that occurs within minutes of exposure and fades within hours.
   Pruritus, commonly known as itchiness, is a sensation exclusive to the skin, and characteristic of many skin conditions.
  
  BULLET::::- Adult blaschkitis
  
  BULLET::::- Aquadynia
  
  BULLET::::- Aquagenic pruritus
  
  BULLET::::- Biliary pruritus
  
  BULLET::::- Cholestatic pruritus
  
  BULLET::::- Drug-induced pruritus
  
  BULLET::::- Hydroxyethyl starch-induced pruritus
  
  BULLET::::- Lichen simplex chronicus (neurodermatitis)
  
  BULLET::::- Prion pruritus
  
  BULLET::::- Prurigo nodularis
  
  BULLET::::- Prurigo pigmentosa
  
  BULLET::::- Prurigo simplex
  
  BULLET::::- Pruritus ani
  
  BULLET::::- Pruritus scroti
  
  BULLET::::- Pruritus vulvae
  
  BULLET::::- Puncta pruritica (itchy points)
  
  BULLET::::- Scalp pruritus
  
  BULLET::::- Senile pruritus
  
  BULLET::::- Uremic pruritus (renal pruritus)
  
  Section::::Psoriasis.
   BULLET::::- About one in four people with PR have mild to severe symptomatic itching. (Moderate itching due to skin over-dryness is much more common, especially if soap is used to cleanse the affected areas.) The itching is often non-specific, and worsens if scratched. This tends to fade as the rash develops and does not usually last through the entire course of the disease.
  
  BULLET::::- The rash may be accompanied by low-grade fever, headache, nausea and fatigue.
  
  Section::::Causes.
   Once affected, the symptoms may not show for several days. The symptoms can be severe burning, itching, swelling and pain in the affected areas. The areas exposed to sunlight may have the appearance of a sunburn - where clothing is worn the skin is protected. There is no known reaction to moonlight, but reflections from windows and mirrors of sunlight can still cause damage.
  
  Section::::Diagnosis.
   Dermatitis symptoms vary with all different forms of the condition. They range from skin rashes to bumpy rashes or including blisters. Although every type of dermatitis has different symptoms, there are certain signs that are common for all of them, including redness of the skin, swelling, itching and skin lesions with sometimes oozing and scarring. Also, the area of the skin on which the symptoms appear tends to be different with every type of dermatitis, whether on the neck, wrist, forearm, thigh or ankle. Although the location may vary, the primary symptom of this condition is itchy skin. More rarely, it may appear on the genital area, such as the vulva or scrotum. Symptoms of this type of dermatitis may be very intense and may come and go. Irritant contact dermatitis is usually more painful than itchy.
   Section::::Cause.:Solar urticaria.
  
  This form of the disease occurs on areas of the skin exposed to the sun; the condition becomes evident within minutes of exposure.
  
  Section::::Cause.:Water-induced.
   BULLET::::- "Crotalaria pallida" pollen may cause an allergic reaction in humans, including swelling of the eyes and face, a rash on the neck and shoulders, and itching. Symptoms may take up to a week to clear.
   Dermatitis is a group of skin conditions that includes atopic dermatitis, allergic contact dermatitis, irritant contact dermatitis and stasis dermatitis. The exact cause of dermatitis is often unclear. Cases may involve a combination of irritation, allergy and poor venous return. The type of dermatitis is generally determined by the person's history and the location of the rash. For example, irritant dermatitis often occurs on the hands of people who frequently get them wet. Allergic contact dermatitis occurs upon exposure to an allergen, causing a hypersensitivity reaction in the skin.
   Many contact sensitizers or irritants are known to cause contact dermatitis superimposed on nummular dermatitis. Studies have implicated nickel, cobalt, chromate, and fragrance as likely culprits. Xerosis, or dehydration of skin is also a likely cause. Infection with "Staphylococcus aureus" bacteria or "Candida albicans" may also play a role.
  
  Section::::Diagnosis.
   Some people can develop a sweat allergy. The allergy is not due to the sweat itself but instead to an allergy-producing protein secreted by bacteria found on the skin. Tannic-acid has been found to suppress the allergic response along with showering.
  
  Section::::Causes.:Hyperhidrosis.
   Children from ages 3 to 7 are most commonly infected with tinea capitis. Trichophyton tonsurans is the most common cause of out breaks of tinea capitis in children, and is the main cause of endothrix (inside hair) infections. Trichophyton rubrum is also a very common cause of favus, a form of tinea capitis in which crusts are seen on the scalp.
   Contact dermatitis
  
  Contact dermatitis is a type of inflammation of the skin.
  
  It results from either exposure to allergens (allergic contact dermatitis) or irritants (irritant contact dermatitis). Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight. Diagnosis of allergic contact dermatitis can often be supported by patch testing.
  
  Section::::Signs and symptoms.
   During damp summers any disturbance of taller plants - e.g. clearing lantana, can produce a shower of tick larvae. When large numbers of larvae attach to a sensitized person, severe allergic dermatitis may result. The maddening rash that results is commonly referred to as 'scrub-itch'. Such outbreaks are seasonal in southeast Queensland and occur most commonly during January, February and March when larval populations are at their peak. Dermatitis is most commonly encountered in rural workers.
  
  Section::::Allergy.:Allergic reactions to nymphs and adults.
   Since contact dermatitis relies on an irritant or an allergen to initiate the reaction, it is important for the patient to identify the responsible agent and avoid it. This can be accomplished by having patch tests, one of various methods commonly known as allergy testing. The top three allergens found in patch tests from 2005–06 were: nickel sulfate (19.0%), Myroxylon pereirae (Balsam of Peru, 11.9%), and fragrance mix I (11.5%).
   A third form of testing is the photoprovocation test which is used to identify disorders instigated by sun burns. The process of this test involves exposing one area of a patient's arm to certain dosage of UVB radiation and one area on the other arm to a certain dosage of UVA radiation. The amount of radiation that the patient is exposed to is equal to that "received in an hour of midday summer sun." If the procedure produces a rash, then the patient will undergo a biopsy. Finally, there are laboratory tests which generally involve procedures such as blood, urine, and fecal biochemical tests. In some situations, a skin biopsy may be performed.
   Another cause of irritation in women is post menopausal vaginitis. The decline in the female sex hormones leads to development of dryness and itching in the vagina. This is often accompanied by painful sexual intercourse. Cracks and tears often develop on outer aspects of the labia which becomes red from chronic scratching. Post menopausal vaginitis can be treated with short term use of vaginal estrogen pessary and use of a moisturizer.
  
  Section::::Types.:Lungs.
  
raw_presuppositions: Hot skin should not feel itchy.
raw_corrections: Hot water and sun on the skin dries the skin out which nakes it itchy.