Miliaria is a common skin disease caused by blockage and/or inflammation of eccrine sweat ducts. Miliaria is also known as heat rash or prickly heat.
Causes
Miliaria develops when some of your sweat ducts clog. Instead of evaporating, perspiration gets trapped beneath the skin, causing inflammation and rash. The main contributing causes are:
- Immature sweat ducts in a newborn child
- A hot and humid environment
- Intense physical activity
- Fever
- Dressing too warmly or too tight, sleep with a thick blanket.
- Hospitalised or bedridden patients
Clinical features
Adults usually develop miliaria in skin folds and where clothing causes friction. In infants, the rash is mainly found on the neck, shoulders and chest. It can also show up in the armpits, elbow creases and groin.
The types of miliaria are classified according to how deep the blocked sweat ducts are. Signs and symptoms for each type vary.
- Miliaria crystallina: affects the sweat ducts in the top layer of skin. Miliaria crystallina presents as 1–2 mm superficial clear blisters that easily break. There is no inflammation.
- Miliaria rubra: A type that occurs deeper in the skin including red, non-follicularpapules and They are very itchy.
- Miliaria pustulosa: is a variant of miliaria rubra with pustules.
- Miliraria profunda: A less common form of heat rash affects the dermis. Retained sweat leaks out of the sweat gland into the skin, causing firm, flesh-colored lesions that resemble goose bumps.
When to see a doctor
Miliaria usually heals by cooling the skin and avoiding exposure to the heat that caused it. See your doctor if you have symptoms that last longer than a few days, the rash seems to be getting worse, or you notice signs of infection, such as:
- Increased pain, swelling, redness or warmth around the affected area
- Pus draining from the lesions
- Swollen lymph nodes in the armpit, neck or groin
- A fever or chills