Miliaria
Encyclopedia
Miliaria is a skin disease marked by small and itchy rash
es. Miliaria is a common ailment in hot and humid conditions, such as in the tropics and during the summer season. Although it affects people of all ages, it is especially common in children and infants due to their underdeveloped sweat glands.
; instead of a rash the patient presents with multiple tiny blister-like lesions that look like beads of perspiration and essentially cause no symptoms.
, sometimes referred to as "wildfire" due to the rapid spread and severe burning sensations, generally occurs as a complication of repeated episodes of miliaria rubra. The obstruction is located deep in the structure of the sweat gland, causing the gland's secretions to leak between the superficial and deep layers of the skin. The rash, and associated symptoms, tend to break out within hours of an activity provoking sweating but similarly fade within hours when the stimulus for the sweating is removed. The rash tends to be flesh-coloured as opposed to the prominent redness of miliaria rubra, and the risk of heat exhaustion is larger.
describes pustules due to inflammation and bacterial infection.
http://dermnetnz.org/hair-nails-sweat/miliaria.html
s, areas of the body that may rub against clothing, such as the back, chest, and stomach, etc. A related and sometimes simultaneous condition is folliculitis
, where hair follicles become plugged with foreign matter, resulting in inflammation.
The symptoms relating to miliaria should not be confused with shingles as they can be very similar. Shingles will restrict itself to one side of the body but also has a rash-like appearance. It is also accompanied by a prickling sensation and pain throughout the region. Those who suspect they have shingles and not miliaria should seek medical advice immediately as the sooner antivirals are taken, the better.
, a common bacterium that occurs on the skin which is also associated with acne
.
The trapped sweat leads to irritation (prickling), itching and to a rash of very small blisters, usually in a localized area of the skin.
It has been suggested that the use of topical antibacterials (including the use of antibacterial soaps) may shorten the duration of symptoms in miliaria rubra even in the absence of obvious superinfection. Other topical agents which may reduce the severity of symptoms include anti-itch preparations such as calamine or menthol
or camphor
-based preparations, and topical steroid creams
. However, caution should be used with oil-based preparations (ointments and oily creams as opposed to water based or aqueous lotions) which may increase blockage to the sweat glands and prolong duration of illness. Other agents have been investigated including supplemental vitamin A and C and vitamin A based medications, but it is worth noting that there is little scientific evidence supporting any of the above treatments in terms of actually reducing the duration of symptoms or frequency of complications.
In most tropical areas the local dispensaries sell Prickly Heat Powder, a talc admixture containing drying milk proteins (Labilin) and Triclosan to fight the infection. These include cooling menthol to help alleviate difficulty getting to sleep. This is an effective treatment — the powder stays on the skin longer and treats bacteria dispersed into bed linens, providing a reasonably dry refuge area for healing. Local wisdom discourages use of Cortisone treatments due to adverse reactions such as hardening of the skin. Consider that miliaria often covers large areas, and generous use of Cortisone may be contraindicated for reasons stated on package warnings. Regular talcum powder will not reduce the rash but can alleviate burning and itching.
In cases where the rash has developed into open blisters or pustular lesions a doctor should be consulted since more aggressive, medically monitored treatment may be required.
Rash
A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...
es. Miliaria is a common ailment in hot and humid conditions, such as in the tropics and during the summer season. Although it affects people of all ages, it is especially common in children and infants due to their underdeveloped sweat glands.
Classification
Miliaria can be classified according to the top level at which obstruction occurs in the sweat glands.Miliaria crystalline
The most superficial obstruction (with the most mild clinical presentation), is known as miliaria crystallineMiliaria crystalline
Miliaria crystalline is a skin condition characterized by small, clear, and very superficial vesicles with no inflammatory reaction....
; instead of a rash the patient presents with multiple tiny blister-like lesions that look like beads of perspiration and essentially cause no symptoms.
Miliaria rubra
The most commonly encountered form of the illness is miliaria rubra, in which obstruction causes leakage of sweat into the deeper layers of the epidermis, provoking a local inflammatory reaction giving rise to the typical appearance of redness (hence rubra) and larger (but still only a few millimetres) blister-like lesions. This form of the illness is often accompanied by the typical symptoms - intense itching or "pins and needles" with a lack of sweating (anhidrosis) to affected areas. There is a small risk of heat exhaustion due to inability to sweat if the rash affects a large proportion of the body's surface area or the sufferer continues to engage in heat-producing activity.Miliaria profunda
The most severe form of miliaria, miliaria profundaMiliaria profunda
Miliaria profunda is a skin condition characterized by non-pruritic, flesh-colored, deep-seated, whitish papules....
, sometimes referred to as "wildfire" due to the rapid spread and severe burning sensations, generally occurs as a complication of repeated episodes of miliaria rubra. The obstruction is located deep in the structure of the sweat gland, causing the gland's secretions to leak between the superficial and deep layers of the skin. The rash, and associated symptoms, tend to break out within hours of an activity provoking sweating but similarly fade within hours when the stimulus for the sweating is removed. The rash tends to be flesh-coloured as opposed to the prominent redness of miliaria rubra, and the risk of heat exhaustion is larger.
Miliaria pustulosa
Miliaria pustulosaMiliaria pustulosa
Miliaria pustulosa is a skin condition, a type of miliaria, that is preceded by another dermatitis that has produced injury, destruction, or blocking of the sweat duct....
describes pustules due to inflammation and bacterial infection.
http://dermnetnz.org/hair-nails-sweat/miliaria.html
Signs and symptoms
Symptoms of miliaria include small red rashes, called papules, which may itch or more often cause an intense 'pins-and-needles' prickling sensation. These may simultaneously occur at a number of areas on a sufferer's body, the most common including the face, neck, under the breasts and under the scrotum. Other areas include skin foldSkin fold
Skin folds are areas of skin where it folds. Many skin folds are distinct, heritable anatomical features, and may be used for identification of animal species, while others are non-specific and may be produced either by individual development of an organism or by arbitrary application of force to...
s, areas of the body that may rub against clothing, such as the back, chest, and stomach, etc. A related and sometimes simultaneous condition is folliculitis
Folliculitis
Folliculitis is the inflammation of one or more hair follicles. The condition may occur anywhere on the skin with the exception of the palms of the hands and soles of the feet.- Causes :...
, where hair follicles become plugged with foreign matter, resulting in inflammation.
The symptoms relating to miliaria should not be confused with shingles as they can be very similar. Shingles will restrict itself to one side of the body but also has a rash-like appearance. It is also accompanied by a prickling sensation and pain throughout the region. Those who suspect they have shingles and not miliaria should seek medical advice immediately as the sooner antivirals are taken, the better.
Pathophysiology
Miliaria occurs when the sweat gland ducts get plugged due to dead skin cells or bacteria such as Staphylococcus epidermidisStaphylococcus epidermidis
Staphylococcus epidermidis is one of thirty-three known species belonging to the genus Staphylococcus. It is part of human skin flora, and consequently part of human flora. It can also be found in the mucous membranes and in animals. Due to contamination, it is probably the most common species...
, a common bacterium that occurs on the skin which is also associated with acne
Acne vulgaris
Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...
.
The trapped sweat leads to irritation (prickling), itching and to a rash of very small blisters, usually in a localized area of the skin.
Prevention
Prickly heat can be prevented by avoiding activities that induce sweating, using air conditioning to cool the environment, wearing light clothing and in general, avoiding hot and humid weather. Frequent cool showers or cool baths with mild soap can help to prevent heat rash.Treatment
Medical assistance should be sought for the first episode of a rash with the appearance of miliaria. The differential includes several conditions which an experienced practitioner should be able to recognise and may require treatment distinct from the usual measures taken for miliaria. In most cases the rash of miliaria will resolve without intervention. However, severe cases can last for a number of weeks and cause significant disability. General measures should be recommended for all patients, including moving to an air-conditioned environment if possible, avoiding sweat-provoking activities and occlusive clothing, and taking frequent cool showers.It has been suggested that the use of topical antibacterials (including the use of antibacterial soaps) may shorten the duration of symptoms in miliaria rubra even in the absence of obvious superinfection. Other topical agents which may reduce the severity of symptoms include anti-itch preparations such as calamine or menthol
Menthol
Menthol is an organic compound made synthetically or obtained from peppermint or other mint oils. It is a waxy, crystalline substance, clear or white in color, which is solid at room temperature and melts slightly above. The main form of menthol occurring in nature is -menthol, which is assigned...
or camphor
Camphor
Camphor is a waxy, white or transparent solid with a strong, aromatic odor. It is a terpenoid with the chemical formula C10H16O. It is found in wood of the camphor laurel , a large evergreen tree found in Asia and also of Dryobalanops aromatica, a giant of the Bornean forests...
-based preparations, and topical steroid creams
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
. However, caution should be used with oil-based preparations (ointments and oily creams as opposed to water based or aqueous lotions) which may increase blockage to the sweat glands and prolong duration of illness. Other agents have been investigated including supplemental vitamin A and C and vitamin A based medications, but it is worth noting that there is little scientific evidence supporting any of the above treatments in terms of actually reducing the duration of symptoms or frequency of complications.
In most tropical areas the local dispensaries sell Prickly Heat Powder, a talc admixture containing drying milk proteins (Labilin) and Triclosan to fight the infection. These include cooling menthol to help alleviate difficulty getting to sleep. This is an effective treatment — the powder stays on the skin longer and treats bacteria dispersed into bed linens, providing a reasonably dry refuge area for healing. Local wisdom discourages use of Cortisone treatments due to adverse reactions such as hardening of the skin. Consider that miliaria often covers large areas, and generous use of Cortisone may be contraindicated for reasons stated on package warnings. Regular talcum powder will not reduce the rash but can alleviate burning and itching.
In cases where the rash has developed into open blisters or pustular lesions a doctor should be consulted since more aggressive, medically monitored treatment may be required.