6 common skin problems in runners

Learn how to prevent or manage some of the most common skin problems affecting runners.

Running offers many health benefits, but repeated friction, pressure, sweating, exposure to the elements and shared sporting environments can also contribute to a range of skin and nail problems. Taking a few preventive measures before and during training can help reduce these risks.

Below we review six common dermatological problems in runners and explain how they can be prevented or managed.

1. Sun damage and skin cancer

Runners who train outdoors may accumulate substantial ultraviolet exposure over time. An observational study published in Archives of Dermatology reported a higher prevalence of certain melanoma risk markers among marathon runners, although this does not establish that running itself causes melanoma. The relevant factor is repeated ultraviolet exposure, which is also associated with photoageing and skin changes such as wrinkles, solar lentigines and actinic keratoses.

Runners who train outdoors should therefore:
avoid unnecessarily prolonged exposure to intense midday sun;
use a broad-spectrum sunscreen with a high SPF, generally SPF 30 or above;
apply it generously before outdoor exercise, following the product instructions;
reapply it when necessary, particularly during long runs or after heavy sweating;
use additional protection such as a hat, sunglasses and suitable clothing, including UPF-rated garments where appropriate.
Some runners find that sunscreen migrates towards the eyes when they sweat, causing stinging. Fluid, gel, stick or sport-specific water-resistant formulations may be better tolerated in these circumstances.

If you notice a new or changing skin lesion, consult a dermatologist specialising in skin cancer.

2. Black toenails

Black toenails are common in long-distance runners. They are usually caused by subungual haemorrhage, or bleeding beneath the nail, resulting from repeated impact between the toes and the inside of the shoe. Ill-fitting footwear, particularly shoes that are too short or tight at the front, can increase the risk. In some cases, the affected nail may eventually detach and regrow. However, dark pigmentation beneath a nail is not always caused by running trauma. Persistent or unexplained pigmentation can sometimes resemble fungal infection or, much less commonly, subungual melanoma. If the cause is uncertain, the pigmentation does not grow out with the nail or there are other concerning changes, assessment by a dermatologist experienced in nail disorders is advisable.

3. Blisters

Blisters are usually caused by a combination of:
friction;
heat;
moisture;
poorly fitting shoes;
socks that crease or move during exercise.
Applying petrolatum or an anti-chafing lubricant to areas prone to friction may help. Appropriate socks that fit well and manage moisture are also important. Antiperspirants may be useful in selected runners with excessive foot sweating. If a blister develops, an intact blister is generally best left unbroken where possible because the overlying skin provides protection. If it is very large, painful or likely to rupture during continued activity, careful drainage may sometimes be appropriate while preserving the overlying skin. The area should then be kept clean and protected with a suitable dressing. Routine use of topical antibiotics is not necessary for uncomplicated blisters. People with diabetes, impaired circulation or reduced sensation in their feet should seek professional advice before treating significant blisters themselves.

4. Chafing

Chafing is one of the most frequent skin problems in runners. It results from repeated friction between skin surfaces or between the skin and clothing, particularly when sweat and prolonged exercise are involved. To reduce the risk:
wear properly fitting technical clothing;
minimise seams in areas prone to rubbing;
change out of wet clothing after exercise;
use petrolatum or a specific anti-chafing lubricant on high-friction areas.
Common sites include the inner thighs, groin, armpits and areas where sports clothing repeatedly rubs against the skin.

5. Runner’s nipple

Runner’s nipple is a form of frictional dermatitis caused by repeated rubbing of a shirt or sports bra against the nipples. It is particularly common during long-distance running and can cause redness, soreness, superficial erosion and occasionally bleeding. Preventive measures include:
applying petrolatum or a suitable anti-chafing product before running;
covering the nipples with protective tape or a dressing;
choosing well-fitting, moisture-wicking clothing.

6. Skin infections and other sweat-related conditions

Heat, sweating, occlusion and repeated friction can create conditions that favour several skin problems. These include:
bacterial folliculitis;
fungal infections of the skin and nails;
viral infections such as warts;
reactivation of herpes simplex in susceptible individuals.
Athlete’s foot, or tinea pedis, is a fungal infection that commonly affects the spaces between the toes and is favoured by warm, moist conditions. Preventive measures include:
keeping the feet clean and dry;
changing damp socks promptly;
allowing footwear to dry between uses;
avoiding walking barefoot in communal showers and changing rooms;
not sharing towels or footwear.

Cold sores can also be triggered in some people by prolonged sunlight exposure. Runners with recurrent herpes labialis should therefore pay particular attention to sun protection for the lips and surrounding skin.

We invite you to share this article about common skin problems in runners with family and friends who may find it useful.