Eczema is a chronic inflammatory skin condition characterized by a compromised skin barrier, making the skin particularly sensitive to environmental factors. For individuals with this condition, hot tubs present a complex challenge that can trigger an eczema flare-up. The combination of high water temperature, concentrated sanitizing chemicals, and the risk of infection poses distinct threats to already fragile skin. Understanding these risks is the first step in deciding whether to use a hot tub and how to mitigate potential negative effects.
How Hot Water Disrupts the Skin Barrier
The high temperatures typical of a hot tub, often reaching 104°F (40°C), are problematic for eczematous skin. Hot water acts as a potent solvent, stripping away the skin’s natural oils (sebum) that form a protective lipid layer. This removal of natural moisturizers accelerates transepidermal water loss (TEWL), leading to increased dryness and itching. Hot water exposure elevates the skin’s surface pH, making it more alkaline and less capable of maintaining its defense function.
The heat also triggers vasodilation, the widening of blood vessels near the skin’s surface. This increased blood flow causes the skin to become redder and warmer, contributing to the sensation of itchiness (pruritus), a common symptom of eczema. Long exposure to hot water is known to damage the skin barrier function, regardless of the water’s chemical content. For a person with eczema, this heat-induced irritation and loss of moisture can quickly lead to an active flare-up.
The Role of Sanitizing Agents in Skin Irritation
Hot tubs rely on strong sanitizing agents, primarily chlorine or bromine, to keep the water clean, but these chemicals are often primary irritants for sensitive skin. These halogen-based chemicals, even at regulated levels, can cause irritant contact dermatitis, manifesting as redness, itching, and discomfort. The sanitizers work by creating acids in the water (hypochlorous or hypobromous acid), which can be harsh and further dry out the skin by damaging natural oils.
Beyond the sanitizers, the water’s pH balance is a major factor in skin irritation. The ideal pH for hot tub water is typically maintained between 7.2 and 7.8, which is slightly above the skin’s naturally acidic pH of around 5.5. If the water becomes too acidic (below pH 7), it can be corrosive and immediately trigger a severe rash or burns on compromised skin. Conversely, if the pH climbs too high, sanitizers become less effective, increasing the risk of bacterial growth while still causing irritation. Some individuals may also react to non-chlorine shock treatments, developing a rash hours after soaking.
Increased Susceptibility to Hot Tub-Related Infections
A serious concern for eczema sufferers is the heightened risk of bacterial infection due to the skin’s compromised barrier. Eczematous skin often has microscopic cracks and areas of inflammation that provide easy entry points for pathogens. This vulnerability is especially relevant in the warm, moist environment of a hot tub, which is an ideal breeding ground for certain bacteria.
The most common hot tub-related infection is folliculitis, often caused by the bacterium Pseudomonas aeruginosa. This bacterium can survive even in adequately chlorinated water by forming a protective biofilm within the hot tub’s plumbing system. When contaminated water contacts compromised skin, the bacteria can infect hair follicles, resulting in a bumpy, itchy, or painful rash, sometimes called “hot tub rash.” People with pre-existing skin conditions or those who have recently shaved or waxed are more susceptible because the skin barrier is less intact.
Practical Strategies for Minimizing Flare-Ups
For individuals who choose to use a hot tub, proactive steps can significantly reduce the likelihood of a flare-up. Before entering the water, apply a protective barrier cream, such as petroleum jelly or zinc oxide ointment, to areas that are actively inflamed or have broken skin. This physical barrier helps repel the chemical-laden water and prevents the stripping of natural skin moisture. It is also important to ensure any open wounds or significant cracks are fully covered with a waterproof dressing, or avoid the hot tub entirely until the skin has healed.
During the soak, keep the duration short, ideally limiting time in the hot water to 10 to 15 minutes to minimize the effect of heat on the skin. Avoid sitting directly near high-pressure jets, as the forceful water combined with heat can increase local irritation. It is also recommended to check the water temperature, ensuring it is not excessively high.
The most critical steps occur immediately after exiting the hot tub, following the “soak and seal” principle used in eczema management. Immediately shower with lukewarm water to rinse off all residual hot tub chemicals and bacteria. Use a mild, fragrance-free cleanser sparingly, then gently pat the skin dry with a clean towel, leaving the skin slightly damp. Within three minutes of drying, liberally apply a prescribed topical medication to any affected areas. Follow this with a generous layer of moisturizer or emollient to the rest of the body to seal the moisture into the skin.