The follicle's four-way argument: sebum, keratin, bacteria, hormones.

A vascular and inflammatory thermostat set too sensitive.

One hair follicle at a time, inflamed or infected.

Not boils, not poor hygiene: a chronic inflammatory disease of the folds.

The rash around the mouth caused by the cream you bought for it.

A barrier gene, an immune bias, and a climate all colliding.

The skin reacting to something it touched, either by chemistry or by memory.

Yeast, oil, and an immune system that over-answers.

Skin turnover running at eight times the speed limit.

Mast cells releasing histamine on a hair trigger.

The immune system attacking the basal layer, in purple.

The Christmas-tree rash that arrives, alarms, and leaves.

The immune system retiring melanocytes patch by patch.

Hormones and UV co-signing a pigment loan the skin keeps paying.

The receipt inflammation leaves in melanin.

Every summer, itemised on the skin.

Wound healing that never received the stop signal.

The mark the operation leaves after the operation succeeds.

Where inflammation dissolved the collagen and the skin sank.

Dermal tears from growing faster than collagen can keep up.

The largest, most complex scars skin can make.

The honey-crusted schoolyard infection.

Dermatophytes eating keratin in an expanding ring.

A virus hijacking keratinocytes into building a tower.

A virus that lives in a nerve and visits the lip when you are run down.

Chickenpox coming back along one nerve.

Pearly dome bumps that a child's immune system will eventually clear.

A mite you cannot see, an itch you cannot forget.

Mostly harmless. The job is knowing which one is not.

Sun damage that is thinking about becoming cancer.

The most common cancer of any kind, and the least dangerous, if it is treated.

Sun damage's second-most common cancer, and one that can spread.

The one every skin website exists to send to a doctor early.

Benign, ugly, and mistaken for melanoma by half the internet.

The butterfly rash and its scarring cousins.

The immune system pausing hair follicles, patch by patch.

A gap in the lip or roof of the mouth that closes in surgery, and a scar that needs care after.

Scale that never sheds: a barrier gene written wrong.

A wiring error in the skin's capillaries, present from birth and there for life.

A benign blood-vessel growth that appears after birth, grows, then shrinks.

Sweat glands with the volume stuck on maximum.

Follicles shrinking under the influence of DHT and inheritance.

The slowest infection in dermatology, living under a plate of keratin.