Most commonly, the skin flakes in the ear are due to seborrheic dermatitis , commonly known as dandruff.  Another common cause is psoriasis . Even chronic scratching of the ear can produce a rash with flaking, called lichen simplex chronicus.

Seborrheic dermatitis of the ear, the most common cause of ear flakes

Ear Psoriasis

Lichen simplex chronicus due to chronic scratching of the ear

Psoriasis, seborrheic dermatitis and eczema can cause flaking, scaling, redness and itching on the back of the ear as well.

There are a number of disorders that can cause a rash in the ear. The conchal bowl (the indented area that leads to the ear canal) can be involved with a number of other skin conditions, including

• acne (lots of hair follicles and sebaceous glands there)
• benign and malignant skin growths, like seborrheic keratoses, basal cell carcinoma and squamous cell carcinoma
• a skin form of lupus, called discoid lupus erythematosus
• shingles, also known as herpes zoster
• impetigo (a bacterial infection)

Discoid lupus erythematosis, ear

Squamous cell carcinoma (skin cancer) of the ear

These conditions require different treatments and may require some additional diagnostic tests. I recommend a consultation with a dermatologist for a more definitive diagnosis and treatment of ear flaking.