Managing common skin conditions in a tropical climate

Dr Tan Hiok Hee
Senior Consultant Dermatologist

Singapore has hot and humid temperatures all year round, and temperatures in the daytime can average 31-32 degrees Celsius, with a relative humidity that can exceed 80%. Tropical conditions such as these can adversely affect the skin, and here are some common conditions which can be affected by the weather and tips on managing them:

Superficial fungal infections

Fungal infections are more common in humid and damp conditions. Locally, athlete’s foot and jock itch are common skin infections that we see. Athlete’s foot, or tinea pedis, is a fungal infection of the soles and toewebs of the feet which results in dry, scaly and itchy skin. It can eventually affect the toenails as well. Jock itch is a ringworm infection around the groins. Another common fungal skin infection is Pityriasis versicolor, which causes whitish, pinkish or brownish scaly patches on the body.

Tips: keep the skinfolds and toewebs as dry as possible. Dry thoroughly after a shower, and people with sweaty feet can consider using antifungal powders in their socks to reduce the risk of athlete’s foot. If you are prescribed an antifungal cream, continue to use it for at least 1-2 weeks after the rash clears, to reduce the risk of a recurrence. Have more than one pair of work shoes and alternate them weekly.

Eczema

Eczema is often aggravated by dry and cold conditions, and some patients actually find that increased humidity does help to reduce itching and flaring of eczema. However, it is also common for eczema to flare with the heat, and excessive perspiration can sometimes be an aggravating factor as well.
Atopic eczema is the most common form and those affected may also have other allergic conditions like asthma. In healthy skin, the cells in the epidermis are able to retain moisture, and this helps it to form a barrier against damage and infection. Hot, humid weather may trigger more itching and scratching or excessive washing of the skin can cause disruption of the barrier function, leading to worsening of eczema. House dust mites, which thrive better in such an environment, can also be an aggravating factor in eczema.

Tips: Moisturising is till important, even though Singapore is humid. Use lighter formulations such as lotions if you do not like the feel of richer moisturisers, but these may not be as effective for people with very dry skin. Do not take long showers – these will dry the skin further, and use gentle or non-soap cleansers. Many patients with eczema feel more comfortable in an air-conditioned environment, but remember to continue using the prescribed creams and moisturisers and try not to set the room temperature too low (generally a room temperature of 24-25 degrees Celsius is comfortable for the majority).

Acne

If one’s complexion is oily, the heat and humidity can make it worse. Regular facial cleansing with a gentle facewash can be done two to three times a day. Beware that certain medications prescribed for acne may make you sensitive to sunlight.

Tips: Use an oil-free sunblock for sun protection. This will not clog your pores and feels more comfortable to use on acne prone skin. If your face or skin turns very red when you are on medications such as doxycycline or isotretinoin, see your doctor. Topical retinoids, which clear blackheads and whiteheads, are used at night, and not in the daytime, to minimise photosensitivity.

Heat rash

Heat rash (Prickly heat) or miliaria is caused when the skin pores become blocked and sweat cannot escape. Adults usually develop heat rash 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.

It cause red bumps to appear, and occasional small clear blisters may also be seen. The rash usually clears on its own.

Tips: Do not wear very tight fitting clothes if you are prone to heat rash. Light cotton clothing is usually recommended.