A large, itchy lump suddenly appeared on the top of the foot without any apparent cause.

May 05, 2023 Source: Cainiu Health

Dr. Liu Wan

Introduction

A sudden, unexplained swelling and itching on the top of the foot may be caused by insect bites. In such cases, patients can use medications like calamine lotion or zinc oxide ointment. It could also be prurigo nodularis, which can be treated with topical creams such as desonide cream or hydrocortisone butyrate cream. Additionally, it might be urticaria (hives), which can be managed with oral medications like dexamethasone acetate tablets or prednisone acetate tablets. Always follow medical advice when using these medications.

In general, the sudden appearance of a lump on the top of the foot accompanied by itching may be caused by insect bites, prurigo nodularis, urticaria, or other factors, and symptomatic treatment is required. Specific analyses are as follows:

1. Insect bites

If the top of the foot is accidentally bitten by insects, it may trigger inflammation, leading to symptoms such as itching, redness, and hives. Patients can use calamine lotion or zinc oxide ointment as directed by a physician. It is important not to scratch the affected area.

2. Prurigo nodularis

Prurigo nodularis may be associated with various factors such as neurological, immune, and psychological factors. It typically presents as firm, edematous red papules with intense itching. Patients can apply topical medications such as desonide cream or hydrocortisone butyrate cream as prescribed. Daily skin moisturization should also be maintained.

3. Urticaria

Urticaria may be related to friction, medications, emotional stress, and other factors, primarily manifesting as hives and itching. Patients may take oral medications such as dexamethasone acetate tablets or prednisone acetate tablets as directed by a doctor. Adequate sleep should be ensured in daily life, and fatigue and staying up late should be avoided.

Additionally, these symptoms could also result from lipoma, common warts, dermatofibroma, or other conditions. It is recommended that patients seek timely medical evaluation at a hospital.

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Itchy top of the foot, scratched until broken, developed large red blisters.

In general, itching on the top of the foot that becomes broken from scratching and develops large red blisters may be caused by conditions such as urticaria, eczema, contact dermatitis, tinea pedis (athlete's foot), or herpes zoster. Targeted treatments are required. Urticaria is an allergic reaction, usually triggered by allergens such as food, medications, or insect bites. This allergic reaction causes the immune system to release histamine, leading to blood vessel dilation and swelling of the skin tissues.