Miliaria Profunda - What Is It?

What Is Miliaria Profunda?

Miliaria profunda, also known as eccrine miliaria, heat rash, prickly heat, or sweat rash, is a common skin disorder that results from blockage or inflammation of the sweat ducts; this disorder is commonly found in hot, humid, and tropical climates. This can affect neonates and adults but is mostly seen in children; the onset of the disease starts within a few days of arrival in tropical regions, which can require months to peak.

Miliaria profunda can be divided into three types based on the sweat duct obstruction at different levels of the skin, which are as follows:

• Miliaria crystallina, also called sudamina, results from obstruction of the sweat ducts near the surface of the skin in the stratum corneum of the epidermis.

• Miliaria rubra results from the obstruction of the sweat ducts in the deeper layers of the skin below the stratum corneum.

• Miliaria profunda or tropical anhidrosis is also a type of miliaria profunda. It is caused due to sweat leaking from the sweat glands into the middle layer of skin following repeated episodes of miliaria rubra, which result in blockage at the epidermal junction. Heat rash can affect all age groups and racial groups.

How Is Miliaria Profunda Caused?

Miliaria is mainly caused by excessive sweating; some of the common risk factors include:

• Immature sweat ducts of infants and children.

• Climatic factors- hot and humid climate.

• Intense physical activity and workout.

• Elevated body temperature.

• The use of synthetic clothes makes it difficult for the skin to breathe.

• Bedridden patients are made to lie on waterproof mattresses.

Other Causes of Miliaria Include:

• Medications: Drugs that induce sweating, like Clonidine and Neostigmine, have been reported to induce miliaria.

• Allergic or Adverse Reactions: Certain therapies or foods can also induce miliaria. As is frequent in people receiving induction chemotherapy.

• Genetic Disorders: Morvan syndrome is a rare genetic disorder characterized by hyperhidrosis and other abnormalities leading to miliaria.

• Pseudohypoaldosteronism Type I: It is also a genetic disorder that has the potential to act as a predisposing factor for miliaria.

• Radiotherapy.

What Are the Signs and Symptoms of Miliaria Profunda?

Symptoms of Heat Rash Vary Depending on Type:

• Miliaria crystallina presents as one to two millimeters of superficial clear blisters that easily break. The blisters can look like beads of sweat. There is no inflammation. The blisters are usually widely spread on the head, neck, and upper trunk. The vesicles break easily to leave a bran-like scale.

• Miliaria rubra, the most frequent type of heat rash, causes red, two to four millimeters of non-follicular papules and papulovesicular papules. They are very itchy. Background erythema is often present. In children, miliaria involves the trunk and the skin folds of the neck, axilla, or groin. In adults, miliaria often affects the upper trunk, scalp, neck, and flexures, particularly in areas of friction with clothing.

• Miliaria pustulosa is a variant of miliaria rubra with pustules.

• Miliaria profunda presents as asymptomatic deep papules. The flesh-colored papules with a diameter of between one and three millimeters appear on the trunk and extremities.

How Is Miliaria Profunda Diagnosed?

Heat rash is diagnosed clinically as it has a typical presentation.

Some cases which are severe and have recurrence might require additional laboratory diagnosis, which includes punch biopsy and histological examination of different forms of the disease. For example, miliaria crystallina shows vesicles associated with the sweat ducts within or just under the stratum corneum of the epidermis, whereas the rubra variant presents with sponginess and vesicles. Tzanck smear is used to differentiate miliaria from other diseases like herpes simplex and toxic erythema of the newborn.

What Is the Differential Diagnosis for Miliaria Profunda?

Some other disorders have a similar presentation as that of miliaria which includes:

• Viral infections like herpes simplex or varicella.

• Cutaneous candidiasis or other fungal skin infections.

• Folliculitis- bacterial or pityrosporum.

• Neonatal acne or erythema toxicum neonatorum.

• Drug rashes.

• Grover disease.

• Arthropod bites.

• Lymphocytoma cutis or cutaneous T-cell pseudolymphomas.

How Is Miliaria Profunda Treated?

As the etiology of the disease is excessive sweat and humid climatic conditions, treatment mainly includes ways to control and reduce sweating to prevent further complications. Specific treatment methods depend on the type of miliaria.

Heat rash can be treated and prevented by using the following strategies

• Work at least a few hours per day in an air-conditioned office.

• Sleep in a well-ventilated, cool room.

• Avoid humid conditions by avoiding tropical climates.

• Avoid wearing too much or too tight clothing.

• Avoid using too much soap and irritants.

• Wear shirts and tops made of breathable synthetic or cotton fibers.

• Take off any damp garments.

• Using cool water compresses and bathing with cool water

• Patients should be educated on the signs of heat exhaustion.

Miliaria Crystallina: Does not require any treatment as it is self-limiting and resolves within a day or two.

Miliaria Rubra: Treatment in patients of this type mainly aims at reducing inflammation. The treatment includes the use of mild local corticosteroids to be applied on the affected site for a week or two.

Antibiotics like Clindamycin are prescribed to prevent superposition by any bacterial infection.

Miliaria Profunda: Any specific treatment for this type is unknown or popularized. Therefore, patients with miliaria profunda are treated symptomatically, and the above methods are used.

Some of the common complications induced by miliaria include:

• Staphylococci mainly cause a secondary infection.

• Impaired thermoregulation.

• Hyperhidrosis in uninfected areas.

Conclusion:

Miliaria profunda, commonly known as eccrine miliaria, is a sweat duct irritation or obstruction. This is frequent in hot and humid locations, as well as other illnesses that produce excessive perspiration, such as medication or genetic abnormalities like Morvan syndrome. Miliaria is characterized by painless pustules, which are raised fluid-filled small blisters. The condition can occur in neonates as well as adults. The onset and length when it reaches its peak are determined by the location of the blister in the dermal layers. The condition is also classified into different types. The condition can be diagnosed by clinical presentation, but some cases require histological examination. Treatment is not always required; mostly, lesions heal on their own within a day or two. Preventive measures like avoiding being out in the sun and wearing airy clothes can prevent the occurrence of miliaria.