What’s Causing Your Heat Rash?

As I have discussed before, I learn a great deal of valuable information from interacting with my skin care community; that in large includes my customers.

Recently when I temporarily discontinued my dark chocolate patchouli soap, it was brought to my attention that it had been a customer’s go to for preventing the onset of heat rash. I decided to research it so that I could better understand what it was about the soap that prevented the outbreak. I’m glad I did.

Heat rash is a most uncomfortable thing to deal with and, according to the New Zealand Dermatological Society¹ , once it’s triggered, an attack of miliaria profunda commonly lasts 5-6 weeks despite the best treatment that can be offered. It is because the plugs formed in the sweat duct openings can only be expelled by the outward growth of the sweat duct cells, which takes several weeks. Therefore, from that standpoint, the best treatment is prevention.

Armed with the information I received from my customer and that uncovered via research, I set out to discover what it is or was in my soap that helped prevent the outbreak. It’s good to know that something works; but it’s better to understand why it or how it works.

G.H. Soaps Ingredient - Patchouli

Patchouli Plant

G.H. Soaps Ingredient - Cacao (Raw Chocolate)

Cacao – Raw Chocolate

What is Heat Rash

miliaria | heat rash

cause Staphylococcus epidermidis (a pathogen); Staphylococci are common bacterial colonizers of the skin and mucous membranes

Heat Rash, caused by Staphylococcus epidermidis (S. epidermidis), also termed Miliaria, is a common disorder of the eccrine sweat glands that often occurs in conditions of increased heat and humidity. Miliaria is thought to be caused an increase in certain normal Staphylococcus epidermidis bacteria which live on the skin. These bacteria produce a sticky substance (biofilm)which blocks the sweat ducts. Leakage of sweat through the walls of the duct behind the block is then responsible for the outbreak. Unlike acne and other forms of folliculitis (razor bumps), miliaria spots do not arise around the hair follicles.

There are four types of Miliaria:

  • Miliaria crystallina or sudamina: caused by obstruction of the sweat ducts close to the surface of the skin and appears as tiny superficial clear blisters that break easily.
  • Miliaria rubra: or prickly heat occurs deeper in the epidermis (outside layer of skin) and results in very itchy red papules (bumps).
  • Miliaria profunda: is the effect of sweat leaking into the dermis (middle layer of skin) causing deep and intensely uncomfortable, prickling, red lumps.
  • Miliaria pustulosa: pustules caused by inflammation and bacterial infection.

The bacterium can cause serious complications. It is one of the many microorganisms that live on the human skin and are either harmless or beneficial – as long they are in balance with other microorganisms. When the balance between the microorganisms is disrupted, they can cause various skin diseases. They can also enter the bloodstream and cause potentially fatal complications, and Staphylococcus epidermidis is one of those microorganisms of the skin flora that can be very dangerous.

Prevention & Treatment

Prevention and treatment seem incomplete. While there is much research regarding S. epidermidis’, there is a lack of knowledge offered to the public in terms of successful prevention and management (outside of its symptoms). And because S. epidermidis is part of the human normal flora, it has developed resistance to many common antibiotics. It seems however, most treatments are aimed at relieving sufferers from the symptoms after the onset as opposed to effective, sustainable prevention.

It is noted that antimicrobial agents are effective in suppressing experimentally induced miliaria, meaining in vitro or in a controlled environment. However, it is obvious that prevention is attainable in human hosts as well. The search led me to several articles in my favorite database, the U.S. National Library of Medicine. Combing through several articles, medical journals and manuscripts helped me to better understand why the soap was effective at preventing miliaria for my customer.

The soap contained a generous amount of patchouli essential oil. Patchouli’s main constituent is Patchoulol: 32.92%. As noted in another post, the antimicrobial impacts of essential oils and their chemical components have been recognized by several researchers for their efficacy against various human pathogens. Essential oils derived from aromatic medicinal plants have been reported to exhibit exceptionally good antimicrobial effects against bacteria, yeasts, filamentous fungi, and viruses. Because of this, essential oils are recognized as having great potential in the field of biomedicine as they effectively destroy several bacterial, fungal, and viral pathogens. The presence of different types of aldehydes, phenolics, terpenes, and other antimicrobial compounds means that the essential oils are effective against a diverse range of human pathogens. 

I also landed upon another interesting article by Evidence-Based Complementary and Alternative Medicine², which lists various essential oils and their antibacterial, anti-viral and anti-fungal activity against human pathogens, including Staphylococcus epidermidis. There is much information reported, but in summary, it identified several, common plant oils that could be very effective at preventing miliaria: garlic oil, tea tree oil (Melaleuca alternifolia), clove oil (Eugenia caryophyllata), pennyroyal (Mentha pulegium), rosemary oil (Rosmarinus officinalis) and thyme oil (Thymus kotschyanus). Research in alternative medicine brings hope to those suffering from miliaria. The idea that handmade skin care with powerful essential oils could aid in the fight against outbreaks is even more profound, especially when antibiotics are the only presented alternative.

I was enlightened by this experience as I learned what causes heat rash and why my product worked. I also understand the distress that likely occurs when there is no solution for heat rash at hand, like the temporary discontinuation. Because my customer shared with me her challenge, I was able to learn more about this bacteria. It also helps G.H. Soaps to provide better and continual solutions. This is exactly how our company came to be so thank you for your continued support and for the gift that keeps on giving, knowledge.

Please note that G.H. Soaps does not give medical advice. The information on this website has not been evaluated by the FDA and is not intended to diagnose, treat, prevent, or cure any disease. It is public information, researched, collected, gathered, shared and commented on.


Kalemba D, Kunicka A. Antibacterial and antifungal properties of essential oils. Curr Med Chem. 2003 May;10(10):813-29. Review. PubMed PMID: 12678685.

Mallappa Kumara Swamy, Mohd Sayeed Akhtar, and Uma Rani Sinniah, “Antimicrobial Properties of Plant Essential Oils against Human Pathogens and Their Mode of Action: An Updated Review,” Evidence-Based Complementary and Alternative Medicine, vol. 2016, Article ID 3012462, 21 pages, 2016. doi:10.1155/2016/3012462

Reichling J, Schnitzler P, Suschke U, Saller R, Essential Oils of Aromatic Plants with Antibacterial, Antifungal, Antiviral, and Cytotoxic Properties – an Overview. Complement Med Res 2009;16:79-90

Staphylococcus epidermidis: emerging resistance and need for alternative agents. Raad I, Alrahwan A, Rolston K.
Clin Infect Dis. 1998 May;26(5):1182-7. Review.