What causes cracked skin at the base of the thumb?

Cracks at the base of the thumb (tiger's mouth) may result from dry or dehydrated skin, friction, exposure to irritants, tinea manuum (fungal infection), or eczema. These can be improved through moisturizing care, reducing friction, avoiding irritants, and medical treatment. If the crack is deep, bleeding, or accompanied by worsening itching, prompt medical attention is necessary.

1. Dry and dehydrated skin: In dry climates or with insufficient water intake, the skin at the tiger's mouth loses moisture, leading to thickening and cracking of the stratum corneum, often accompanied by tightness. It is recommended to apply moisturizing cream or petroleum jelly daily, increase fluid intake, and avoid frequent contact with hot water.

2. Friction irritation: Prolonged gripping or manual labor involving pressure on the tiger's mouth can cause repeated friction, damaging the skin’s outer layer and resulting in cracks. Wearing cotton gloves to reduce friction, avoiding forceful gripping of hard objects, and timely skin care after work are advised.

3. Contact with irritants: Frequent exposure to chemicals such as detergents or disinfectants can damage the skin barrier and lead to cracking, sometimes accompanied by mild stinging. Wear rubber gloves when handling these substances, rinse hands with lukewarm water afterward, and apply hand cream promptly.

4. Tinea manuum (hand fungus): A fungal infection affecting the skin at the tiger's mouth damages the stratum corneum, causing dryness, flaking, cracking, and significant itching. Under medical guidance, patients may use antifungal medications such as miconazole nitrate cream, terbinafine hydrochloride cream, or itraconazole capsules to relieve symptoms.

5. Eczema: Localized skin inflammation triggered by internal and external factors manifests as redness, papules, and fissures, with intense itching and a tendency to recur. Under medical supervision, treatments such as desonide cream, calamine lotion, or loratadine tablets may be used to alleviate discomfort.

Maintain hand hydration, choose gentle cleansers, always wear gloves when handling irritants, minimize friction on the tiger's mouth area, avoid excessive water exposure until cracks heal, and consume foods rich in vitamins to support skin repair.