What is a comedo?
A comedo (plural comedones) is plugged in follicular orifice.
- Open comedones (blackheads) are gray, orange, brown, or black papules. The keratinous contents can be expressed or extracted.
- Closed comedones (whiteheads) are non-inflamed, skin-colored papules. They must be pierced to remove their contents.

Open comedones

Closed comedones
What conditions are characterized by a comedo?
Lesions and skin conditions in which prominent comedones are present include:
- Acneespecially common acne and comedonal acne
- Hidradenitis suppurativa
- Solar comedones (senile) and Favre Racouchot syndrome
- Discoid lupus erythematosus
- A seborrheic keratosis (best seen in dermoscopy)
- A compound or dermal papillomatous melanocytic nevus or Mole (best seen in dermoscopy)
- A new comedian
- A epidermal cyst (giant eater)
- A dilated pore of Winer
-
Dilated pores.
Comedones

Comedonal acne

Comedones in hidradenitis suppurativa

solar comedones

Discoid lupus erythematosus

Dermatoscopy of seborrheic keratosis. The rectangles highlight the comedones.

Papillomatous nevus

Comedone naevus

Giant comedo

Multi-headed comedo cyst