What may cause a red blotchy rash inside of calves?

Several factors can cause a rash on the calves. Some include:

_1. Allergies_

Various allergens can cause contact dermatitis—hives, rashes and inflammation resulting from contact with certain elements. Common allergens that can cause calves rash include:

- Metals, such as jewelry

- Clothing with certain synthetic fibers

- Cosmetics and beauty products

- Medications or topical skincare creams

- Dust

- Pollen

- Animal fur

_2. Insect Bites and Stings_

Bites from insects like spiders, mosquitoes, and bees, can sometimes cause a red rash on your calf. Some insect stings may cause severe and life threatening symptoms, such as difficulty breathing, swelling on your face, tongue or lips, or chest pain.

_3. Eczema_

Eczema is a skin condition that can cause dry, red, and itchy patches on the skin. There are several types of eczema, including atopic eczema and contact dermatitis. Atopic eczema is a chronic skin disease that is often inherited and is associated with allergies.

_4. Psoriasis_

Psoriasis is another chronic skin condition that causes red, scaly patches on the skin. It can affect any part of the body, including the calves. Psoriasis is an autoimmune disease, meaning that the immune system attacks the body’s own tissues.

_5. Sunburn_

A bad sunburn can cause a rash on the calves, especially if it’s a severe burn. Sunburn can also cause the affected skin to become red, itchy, and even painful.

_6. Cellulitis_

Cellulitis is a bacterial skin infection that can cause fever, chills, fatigue and a red, swollen, and painful patch on the skin—particularly on the calves. Cellulitis can spread deeply to underlying tissue and can become serious if not promptly treated with antibiotics.

_7. Tinea Cruris or Jockey Itch_

A red rash may indicate a fungal infection called dermatophytosis, also known as ringworm. One variant is known as tinea crucis or jock itch. Typically affects calves, scrotum, and thighs. Itchiness and a burning sensation are common with this rash. Ringworm is contagious—spread from person to person.

_8. Drug Rash_

A red rash may be a sign of drug allergy. Some drugs that may cause a rash include Penicillins, nonsteroidal anti-inflammatory drugs, certain chemotherapy medications and antiviral drugs.

If the red rash on your calf doesn’t get better on its own, or you experience additional symptoms, it's recommended you see a doctor for proper diagnosis and treatment. Self-medication or ignoring a persistent rash can be dangerous.