Post-inflammatory erythema (PIE) is a common skin condition that many people struggle with, especially after dealing with acne or other inflammatory skin conditions.

Dr Sanjeev Yadav, MD, consultant dermatologist of Nepal Police Hospital, Maharajgunj, explains its primary causes and prevention.

What is post-inflammatory erythema?

This common skin issue causes red or pink discolouration due to various inflammatory conditions commonly seen after acne. It appears as red or pink spots caused by skin injury, which leads to the dilation of capillaries in the skin. It is mostly a temporary issue which can be prevented to an extent but might lead to low self-esteem and psycho-social distress if not treated early.

What are the primary causes of post-inflammatory erythema?

PIE occurs when inflammation or injury dilates small blood vessels near the skin’s surface, resulting in red, pink, or purplish marks that linger after the initial issue has healed. One of the most common causes of PIE is acne, particularly inflammatory lesions such as papules, pustules, and nodules. These breakouts trigger a response in which blood vessels expand, and even after the acne resolves, the redness can persist due to the slow recovery of the vascular system. The severity of PIE often depends on the depth and intensity of the acne lesion, with more severe inflammation leading to prolonged erythema.

Another major contributor to PIE is skin picking and scratching, which further aggravates inflammation and delays healing. When the skin undergoes repeated trauma from picking at acne, scabs, or other irritated areas, the injury prolongs blood vessel dilation, making redness more noticeable and long-lasting. This habit not only worsens PIE but may also increase the risk of scarring.

Inflammatory skin conditions like rosacea, which is associated with persistent redness, flushing, and visible blood vessels, can lead to PIE due to chronic inflammation of the skin’s vascular system. Conditions like contact dermatitis and acute eczema also contribute to PIE by triggering skin irritation and inflammation, causing prolonged vascular dilation and lingering redness. Inflammatory reactions to allergens or irritants can create enough damage to the skin that erythema persists even after the underlying condition has improved.

Specific skincare treatments and procedures can also play a role in PIE development. Cosmetic procedures like microdermabrasion and chemical peels, which are designed to exfoliate the skin, can sometimes cause excessive irritation, leading to prolonged redness and inflammation. Similarly, overusing strong, active ingredients like retinoids, benzoyl peroxide, and exfoliating acids can weaken the skin barrier, making it more prone to inflammation-induced erythema. Some laser treatments, particularly those that generate heat, may initially cause vascular dilation, temporarily worsening PIE before improvement occurs.

Does PIE require a different skin care approach for various skin types and sensitivities?

There are six skin types ranging from I-VI and type I-III, which are considered fair skin types, and these skin types are more prone to skin burn and erythema formation than type IV-VI. As fair skin types are more sensitive to UV damage, they require a stronger approach and frequent care, mostly against UV radiation, to prevent PIE.

How can someone with acne or other inflammatory skin conditions prevent PIE from developing in the first place?

Avoiding simple skincare mistakes and adopting proper habits can prevent PIE development. Avoid scratching or picking of skin as it causes capillary damage and aggravates PIE. Similarly, avoid harsh and irritant chemicals for skin cleansing.

Regularly use moisturisers and sunscreens to maintain skin barrier function and UV-induced damage. And lastly, treating any inflammatory skin condition in its early stage can prevent PIE from developing in the first place.

What are some skincare mistakes that worsen PIE or prolong its healing?

Some common but preventable mistakes like harsh scrubbing and cleansing using harsh soap and cleansers instead of gentle cleansing can worsen PIE. Similarly, overwashing and not confining oneself with regular use of moisturisers and sunscreens may worsen and prolong PIE.

How does sun exposure impact PIE, and what SPF recommendations do you have for people dealing with it?

Sun exposure causes UV radiation-mediated skin cell damage, leading to erythema and skin burning, eventually worsening the PIE. Sun protection is important in preventing PIE, and one should always use SPF 30 or more for better sun protection.