Acne on one side of the face: causes and care

When acne sits mostly on one side of the face, the first thing to check is what touches that side more than the other. The few studies of one-sided acne point to contact: a phone held to one ear, rubbing from gear, or heat. Hands, pillows and hair products can add oil or friction to one side as well. This guide covers what the studies found, what commonly touches one side of the face, a rash that can look similar, and what to change first. It is part of Skinli's guide to acne by face area.

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What studies say about acne on one side

Only a few reports look at acne on one side of the face, and they are small.

A phone. A 2020 letter from India described 13 patients seen by video call during the COVID-19 lockdown. They reported new acne, or worse acne, "mainly involving one side of the face." The doctors found "worse disease severity on the side of the face that came in most frequent contact with a cell phone while talking". All of the patients said they had used their phones more during the lockdown. The authors were open that their reasons were guesses: "we speculate that dissipation of heat from the cell phone, friction, trapping of sweat and oil" may trigger acne. In plain words, heat from the phone, rubbing, and sweat and oil held against the skin.

Heat. The same letter mentions a 1981 paper that linked acne on one side of the face to heat, "such as sleeping on one side, washing and bathing with hot water". Skinli did not read the 1981 paper itself, so this is the letter's summary of it.

A facial nerve problem. A 2018 case report describes a young woman whose acne appeared on one side of her face after facial nerve palsy, a weakness of the muscles on that side. The acne appeared on the weak side. The authors wrote that "an increased sebum excretion rate and the immobility of the affected area are most likely what caused the unilateral acne lesions." Sebum is skin oil, and unilateral means on one side.

Rubbing in general. A 2015 review of skin problems caused by rubbing says one type "corresponds to a flare-up of acne in areas prone to the condition." So rubbing on one side can cause a flare of acne in skin that already tends to break out.

What touches one side of the face

What touches one side	What the sources say	Source
A phone held to one ear	Worse acne on the phone side in 13 patients	2020 letter
A hand resting on the cheek or chin	"Touching your face throughout the day can cause acne to flare."	AAD
A helmet, chin strap or other gear	"Anywhere that equipment rubs, acne can appear."	AAD
Hair that falls on one side, with hair products	Oil from hair products can clog pores along the hairline and forehead	AAD
A pillowcase and sheets	The AAD says to wash them when hair products cause acne	AAD

Hands. The American Academy of Dermatology (AAD) says: "Keep your hands away from your face. Touching, picking, and popping can worsen acne." If you rest one hand on the same cheek while you read or work, that side gets more touch.

Gear. The AAD says acne from equipment appears "when sports equipment or clothing traps heat and sweat on your skin." If a strap or a pad sits more on one side, the acne can too. It also warns about shared gear: if you use it and then wipe your face, "you can spread acne-causing bacteria and oil from the equipment to your skin".

Hair and pillows. The AAD says the oils in hair products can cause breakouts along the hairline and forehead. It also says to wash everything your head touched, including "Pillow cases and sheets". The pillowcases and acne guide covers pillowcases and sleeping position. The hairline acne guide covers hair products.

Is acne on one side hormonal?

No source read for this guide says hormonal acne shows up on one side of the face. The NHS lists "changes in hormone levels, such as during puberty, periods, menopause and pregnancy" among the causes of acne in general. The reports on one-sided acne all point to something local, such as a phone, rubbing or heat. If you also have irregular periods, new hair growth on the face or hair loss on the head, see a doctor. The adult acne guide covers hormones.

A one-sided rash that is a different problem

Some rashes on one side of the face are contact dermatitis, an itchy rash where the skin reacts to something that touches it. The AAD says nickel is a common cause, and that "This metal is also found in cell phones, laptops, and other tech devices." A 2014 review found "Thirty-seven cases of mobile phone-related ACD", where ACD means allergic contact dermatitis. It says metals, nickel and chromium in particular, were often the cause of these phone rashes. The AAD lists contact dermatitis under eczema. The AAD lists itchy skin, dry skin that may crack, and blisters among its signs.

Folliculitis, an infection of the hair roots, is another look-alike. The AAD lists "Touching or rubbing your skin frequently" among its causes, and says each spot may have a red ring. A dermatologist can tell these apart.

What to change first

1. Find the contact. Think about what touches the side that breaks out: the ear you use for calls, the hand you lean on, a strap, the side you sleep on, the side your hair falls.
2. Switch sides and clean the phone. The 2020 letter advised: "To prevent such flares, cell phones should be regularly cleaned." It added: "Contact with skin can be reduced by rotating sides."
3. Keep your hands off. The AAD links touching, picking and popping to worse acne.
4. Pad the gear. The AAD says: "Place clean, soft padding between the equipment and your skin."
5. Treat all the skin that breaks out. The AAD says: "To prevent new blemishes, spread a thin layer of the acne medication evenly over your acne-prone skin." It says adapalene, a retinoid, is sold without a prescription.
6. Give it time. The AAD says: "Give treatment six to eight weeks to work." For acne from rubbing, it says: "Acne mechanica tends to clear more quickly than regular acne."

Do not squeeze the spots. The NHS says "do not pick or squeeze spots because this can cause scars". Should you pop a pimple explains why.

When to see a doctor

• Acne on one side has not improved after six to eight weeks of steady treatment.
• You have deep, painful lumps, or the acne leaves scars or dark marks.
• An itchy rash appears where a device or jewelry touches your face.
• You also have irregular periods, new hair growth on the face or hair loss on the head.
• A lump on the face is hot, painful and swollen: the NHS advises an urgent GP appointment for a boil on the face.

Acne on the cheeks, the jaw and the neck has its own guides: acne on the cheeks, jawline acne and neck acne.