We call rash the appearance of one or more red blotchy rash. The rash may be asymptomatic, but in most cases, is accompanied by other symptoms such as itching, fever or local pain.
As there are dozens of diseases that can cause red spots on the skin, from allergies to infections, the presence of these other symptoms associated help us to establish the most likely diagnosis.
In this article we will talk about the 8 most common causes of itchy rash, or red spots on the skin that cause itching.
The following causes of itchy rash will be addressed in this text:
Urticaria is one of the most common causes of pruritic rash. About 20% of the population have at least one episode of illness in your life.
The hives to allergies are the most common and usually appear soon after contact with the causative agent. The time varies from a few minutes to 1 or 2 hours. The main causes are:
Foods, such as eggs, milk, shellfish, soybeans, colorants (including natural), walnuts, and peanuts.
Contact with substances including plants, pollen, animal saliva, ink, resins, perfume, detergent ...
Despite often being treated as an allergic process, the truth is that hives can also be triggered by non-allergic reactions. Viral or bacterial infections, parasites, exposure to heat or cold and physical exercise are just some examples of non-allergic triggers of hives.
The hives of skin lesions are usually multiple, reddish and itch intensely. The spots usually have raised and can have varying sizes, but are generally always rounded. In some cases, the red spots can coalesce and form large plaques. When pressed with your finger, urticaria injury tends to vanish ephemeral way, returning to take the red so removed the finger.
Acute urticaria lasts a few days, usually 1-5, but there are cases that can take a little longer to go away. Throughout the day new lesions can appear, and older may disappear, creating a transient and migratory pattern of the rash. Each lesion individually usually disappear within 24 to 36 hours.
Pityriasis rosea is another extremely common thing red spots on the skin with intense itching. We do not know exactly why the disease arises, but studies suggest that it is caused by some viruses of the family of human herpesviruses such as human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7), the same causing the children a completely different disease called sudden rash or child roseola or pityriasis rosea is another extremely common thing red spots on the skin with intense itching. We do not know exactly why the disease arises, but studies suggest that it is caused by some viruses of the family of human herpesviruses such as human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7), the same causing the children a completely different disease called sudden rash or child roseola.
Despite being a likely viral skin rash, pityriasis rosea is not contagious.
In most cases, the rash began with a single rounded lesion with a pink color with a slight flaking and usually the size of a coin. A few days later, new lesions, similar to the first, but smaller, begin to emerge the trunk and around the groin. These red spots can be very itchy and take 1-3 months to disappear. During this period, new lesions can go arising throughout the body.
Over the days, the lesions are acquiring a form of ring, with lighter center and reddish edges and flaking.
Atopic dermatitis, also called atopic eczema, is a skin rash that is usually well itchy, especially at night. It is a very common rash in infants and children, but can also affect adults. In about 85% of cases, atopic dermatitis arises within the first 5 years of life.
Atopic eczema is a chronic condition with periods of improvement alternating with phases of worsening rash. About 40% of children no longer have the disease spontaneously when they reached adulthood. In the remaining cases, this dermatitis has no cure, staying for life.
The causes of atopic dermatitis are unknown. Despite its name suggests an allergic process, we now know that atopic dermatitis is not an allergy, but a problem arises from genetic defects of some proteins of the skin.
Atopic dermatitis usually appear in skin folds, such as the folds of the knees, the neck and the folds of the elbows. Signs and symptoms of atopic dermatitis can vary greatly from person to person. The most common are:
Intense itching, which is often worse at night.
Spots or reddish / brown plaques, especially in the hands, feet, ankles, wrists, neck, upper chest, eyelids, creases of the elbows and knees. In children, the face and scalp are also commonly affected.
Mosquito bites are common causes of red spots on the skin itchy. During the bite, the mosquito injects its saliva, which has anticoagulant action is the mosquito's saliva that is known to cause allergic reactions in people. In most cases, the reaction to the sting is small and localized, being the most common symptom of a small increase in reddish skin with intense itching.
Symptoms of bites usually occur within 20 minutes and can take up to two days to disappear. The more sensitive a person is to the mosquito's saliva, longer and more intense is often the reaction to the sting. Initially, the injury can be high, with a lighter center and reddish edges. As the days passed, the lesions are more homogeneously flat and red.
Some people are more sensitive than normal to mosquito bites, developing a framework called scrofulous prurigo. These are people who, after a single bite, develop various reddish and itchy lesions, as if they had been attacked by several mosquitoes at the same time in different parts of the body. In scrofulous prurigo, injuries can last up to one month.
Contact dermatitis is a skin irritation caused by direct contact with some irritant. There are two forms of contact dermatitis. The most common is that caused by skin contact with naturally irritating substances, ie substances that cause irritation in almost everyone. The second way is skin contact with substances in which the patient is allergic. They are usually substances that cause no reaction in the skin of most people, only those who are allergic, such as people who are allergic to latex gloves.
Various substances and objects can cause contact dermatitis, including: jewelry, poison ivy plant, latex, perfumes, rubber, leather, soap, etc.
The main contact dermatitis sign is the emergence of a reddish rash that causes itching in allergic form, and irritating form causes burning. Small blisters and cracked skin may also occur. Contact dermatitis lesions tend to be restricted to areas of skin that came into contact with harmful substance.
In most cases, this dermatitis disappears after a few days if the patient has no more contact with the substance that triggered the injury.
Superficial fungal infections of the skin are called dermatophytosis or ringworm. The dermatophyte fungi, i.e., that cause dermatophytosis, are the genera Trichophyton, Microsporum or Epidermophyton. Dermatophytosis is a different ringworm of candidiasis, which usually causes intertrigo (see the next section).
Dermatophytoses can affect various areas of the body such as the scalp, feet, beard, fingernails or trunk and limbs. The skin fungal infections are contagious and can be transmitted by contact with bedding, towels or ordinary clothes.
The main symptoms of skin ringworm are itching and local redness. The tinea usually begins with a reddish plaque or stain and oval in shape, whose center tends to fade with each passing day. If left untreated, the lesions tend to expand in the shape of circles. The tinea cruris, which is the ringworm that affects the groin, can also present as a large red sign on the inner side of both thighs.
The candidiasis intertrigo is a fungal infection of the skin caused by the fungus Candida, which mainly affects the intertriginous areas, or areas where there is contact of two skins, such as the groin, armpits, scrotum, lower region of the breasts or area between the toes.
These fold areas are particularly susceptible to the appearance of intertrigo, since they are moist and hot regions, which favors the proliferation of bacteria, especially of fungi.
Candidiasis skin is manifested by well reddish patches on the skin, with mild flaking and small red dots around it. These lesions may itch and burn and are located in areas of the skin folds.
In babies, candidiasis of skin is common in areas covered by the diaper.
Scabies, popularly known as scabies, is a skin disease caused by the mite Sarcoptes scabiei. Scabies is a contagious infection, which can spread quickly through close physical contact, like that occurs between people who live in the same home or with children in day care.
The classic symptom of scabies is a diffuse itching throughout the body, which is typically more intense at night. Typical lesions of scabies are small dots or red and embossed dots. In some cases, the lesions can be so small that it can be camouflaged by scratches caused by intense itching.
The sites most affected by scabies are the hands, wrists, elbows, armpits, nipples, areas around the navel, genitals, knees, buttocks, thighs and feet. Their backs are usually spared and the head, palms and soles usually only be affected in children.
