A Family Doctor's Tale - MILIARIA

DOC I HAVE PRICKLY HEAT

Prickly heat or miliaria is common in the tropical climate because of the heat and humidity. They appear as itchy red rashes all over the body especially the back and groins and armpits. All National Service army boys in Singapore are given prickly heat powder which eases the discomfort of the rashes and cools the skin of the body down. Frequent showers and thorough drying of the skin after a shower will help prevent this condition.

Prickly Heat(also known as miliaria) is a common non contagious disease which appears as acute itchy red rash on the  body due to retained sweat.

People of all ages are affected  but it is more common in children and infants due to their underdeveloped sweat glands.

It is more common in hot and humid conditions.



There are several types of Miliaria:
I.Miliaria crystallina-
minute superficial vesicular lesions that normally do not cause any symptoms

2.Miliaria rubra -
deeper layer inflammatory lesions causing the typical appearance of redness (hence rubra) and larger blister-like lesions. 

There is intense itching with a lack of sweating  to affected areas. 

This is the most common form of prickly heat.

3.Miliaria profunda-
the most severe form of miliaria due to the rapid spread and severe burning sensations. 

The obstruction is deep in the structure of the sweat gland resulting in the sweat to leak between the superficial and deep layers of the skin. 

The rash occurs within hours of an activity provoking sweating and disappear within hours when the stimulus for the sweating is removed. 

The risk of heat exhaustion is higher.

The cause is the result of the keratin or dead skin cells or bacteria such as Staphylococcus epidermidis of the skin blocking the sweat ducts.

The occluded sweat ducts ruptures when sweating occur and the sweat form an intraepidermal vesicle which leads to irritation(prickly sensation) and itchiness.

Secondary infection may occurs from invasion of staphalococcus.

Symptoms:
1.Occurs in humid hot weather

2.Small red papulovesicular rashes

3.Occurs on the face, neck, under the breasts, trunk, under the scrotum, skin folds, behind knee and antecubital fossa.

4.Usually very itchy

5.Rash usually presents with prickly sensation hence the name Prickly Heat Rash

1.Symptoms and signs of small rashes occuring in hot humid condition with itchiness and prickly sensation

2.Skin scraping for microscopic examination.

Complications are:
1.Fungal infection

2.bacterial infection

Treatment is by:
A. Cool Environment
1. air-conditioned environment

2. avoid heat and sweat-inducing activities

3. avoid occlusive clothing,

4. take frequent cool showers.

B. Medicines:
1. topical antibacterials may reduce the symptoms in miliaria rubra

2. anti-itch preparations such as calamine or menthol  preparations

3. topical steroid creams,

4. Avoid oil based preparations because they increase blockage to the sweat glands.

5. Oral Antibiotics may be given if there is secondary infection.

6. Oral antihistamines may be given if itch is troublesome.

7. Vitamin C or A in high dosages have not been found to be effective

Prognosis is:
Generally good to excellent but may recur.

Environmental factors like humidity and heat should be avoided.


Prevention is by:
1.Good skin hygiene

2.Healthy lifestyle with balanced diet and adequate sleep.

3.Wear light clothing

4.Reduce sweating (use air conditioner)

5.Frequent showers should help

6.Avoid heat and humidity.