Acne on Legs: Causes, Treatment, Similar Conditions and More

• Acne on the legs is often mistaken for similar conditions such as folliculitis or keratosis pilaris
• The types of acne that do develop on the legs are acne mechanica and acne inversa.
• Leg acne is usually treated similarly to other forms of the condition, such as acne vulgaris
• Acne inversa can be severe and particularly painful and may require a professional treatment such as laser surgery

What people understand to be acne on the legs is often a similar condition such as folliculitis, keratosis pilaris, or eczema. However, both acne mechanica and acne inversa do appear on the legs, in the groin and thigh area. While typically treated similarly to more common forms of the condition such as acne vulgaris, acne inversa can be severe and painful and may require professional treatment.

Do You Have Acne On Your Legs? 

When acne develops on the legs it’s usually a form of the condition called acne mechanica, which typically appears on the inner thighs. Although rare, acne inversa, aka hidradenitis suppurativa, is a type of acne that forms on the inner thighs. Acne inversa is a moderate to severe form of acne that can produce painful pus-filled bumps under the skin

However, most of the time what people believe to be leg acne is instead one of several similar conditions, such as folliculitis or keratosis pilaris.

Common Causes  

Acne results when a combination of bacteria, sebum, and dead skin cells become trapped in hair follicles and clog the pores, leading to inflammation. It can appear anywhere on the body, including the legs, although it more commonly forms on the face, and to a lesser extent, the chest and back. 

When true acne does appear on the legs it’s likely to be a form of the condition called acne mechanica. Anyone can develop it because, unlike acne vulgaris, which often has hormonal roots, acne mechanica is completely physical and triggered by excess heat combined with steady friction rubbing against the skin, typically caused by athletic equipment or tight-fitting clothing or undergarments.

When an object consistently rubs against the skin it can trap heat and sweat in the hair follicles, clogging them up. As the rubbing continues, the pores grow more irritated and gradually become inflamed, creating small blemishes that grow into larger pimples.

Acne mechanica varies in appearance from small comedones to inflamed papules and pustules, depending on its severity and the stage of its progression.

The other form of acne that forms on the legs is called acne inversa. The exact cause of acne inversa remains unknown but is believed to result from a combination of genetic and environmental factors. Recent studies indicate that, similar to other types of acne, it begins when hair follicles become blocked, and with respect to the legs, it only appears on the groin. While hormonal factors do not play a role in its development, post-pubescent women in their teens and twenties are twice as likely as men to be affected by this type of acne.  

Treatments for Leg Acne

With the exception of severe cases of acne inversa, leg acne is addressed similarly to acne on the rest of the body, although usually as a spot treatment.

Benzoyl peroxide cleansers

Benzoyl peroxide is one of the most ubiquitous ingredients found in anti-acne skin care products, such as cleansers, toners and treatment gels. It effectively treats blackheads, whiteheads and pimples by penetrating the skin and killing acne-causing bacteria while reducing redness and inflammation.

While frequently combined with other acne medications like salicylic acid and/or topical retinoids as a preventive solution, benzoyl peroxide is applied as a spot treatment to treat leg acne.

Topical retinoids

Topical retinoids are another mainstay treatment for moderate to severe acne and work by unclogging the pores, enabling other medicated creams and gels (such as salicylic acid or benzoyl peroxide) to penetrate them and function more effectively. When taken orally, retinoids reduce outbreaks by curbing the body’s production of sebum.

For leg acne, however, topical retinoids are most appropriate as a spot treatment that can be directly applied to acne mechanica once a day.

Antibiotics

Topical antibiotics reduce bacteria within the hair follicles and possess an anti‐inflammatory and mild comedolytic effect; their bacteriostatic activity based on interaction with ribosomal subunits and the inhibition of protein synthesis. For mild to moderate acne mechanica on the legs, topical antibiotics are used as a spot treatment, usually in combination with another acne medication like benzoyl peroxide.

Oral antibiotics such as tetracycline, erythromycin, minocycline and amoxicillin/clavulanate potassium are sometimes prescribed for moderate cases of acne inversa to treat infected lesions, as is an erythromycin-based skin cream. 

Laser surgery

In cases of severe, painful acne inversa, laser surgery is one option used to clear new and deep-seated breakouts

Similar Conditions

People commonly confuse acne on legs with other skin diseases that manifest in similar blemishes. These include:

Folliculitis

Folliculitis is caused by an inflammation of one or more hair follicles in a specific area.  As with acne mechanica, it often results from steady friction rubbing against the skin that enables bacteria to enter the pores.

What it looks like 

Folliculitis usually manifests as pustules centered on individual hair follicles. These pustules typically vary in size from 2–5 mm, and are often surrounded by a rim of pink or red inflamed skin. Folliculitis looks very similar to acne pimples or crusty sores.

The small bumps caused by folliculitis appear when hair follicles swell up after being infected by yeast or bacteria. These sores can occur anywhere there is hair on the body, but are most common on the neck, legs, armpits, and buttocks. These tiny blister clusters are sometimes colloquially referred to as razor bumps or barber’s itch.

Keratosis pilaris

Keratosis pilaris is typically a minor skin condition that causes small white or reddish bumps or patches to appear on the skin. It’s caused by an excess of the skin protein keratin which blocks the pores and results in the formation of these blemishes.  Keratosis pilaris is usually a genetic condition that often occurs alongside other skin conditions like dermatitis.

What it looks like 

The small, hard, flesh-coloured or white bumps of keratosis pilaris have an acne-like appearance and are commonly found on areas of dry skin such as the upper thighs.

Hives    

These raised, itchy, red or skin-tone welts are frequently mistaken for acne due to their similar appearance. Hives, aka urticaria, can appear anywhere on the body, and usually appear suddenly — either as a reaction to certain allergens, or for unknown reasons.  

What it looks like 

Hives vary in size and can join together to form larger areas known as plaques. They typically last from between a few hours to a full day before fading.

Eczema

Eczema, a form of dermatitis, is a skin disease characterized by a red, itchy rash that may include small blisters. There are several different varieties of eczema, which is most commonly spawned by an allergic reaction or dry skin. Eczema that forms on the legs typically occurs on the knees and is a form of the condition called atopic dermatitis.

What it looks like  

Atopic dermatitis is characterized by small, rough, reddish or dark brown bumps (or ash gray for people with dark skin tones) that can be mistaken for acne. They will sometimes develop into thick, leathery patches of skin.

Takeaway

Usually what people believe is acne on the legs are actually similar conditions such as folliculitis, eczema or keratosis pilaris. That said, when acne does appear on the legs it’s likely to be one of two variations of the condition, acne mechanica or acne inversa. While both conditions are typically treated similarly to other forms of acne, acne inversa can sometimes be severe and particularly painful. In these instances it may require a professional treatment such as laser surgery.