Acne is a disease of sebaceous glands. Caused, many believe, by an increase in hormones brought on by the onset of puberty. Although primarily a ‘teenage’ affliction, acne has been known to continue well into adulthood and in some has become a life long battle.

There are several factors that contribute to acne and its proliferation. The key players however are the hair follicles and sebaceous glands. The hair follicle is a small tubular cavity from which hair grows and into which the sebaceous glands open. Hair follicles are found everywhere on the body except the palms of the hands and the soles of the feet.

The sebaceous glands are small oil producing glands that open into the hair follicle and whose general purpose is to keep the hair and skin lubricated. The sebaceous glands produce an oily substance called sebum that drains into the follicular canal and eventually onto the surface of the skin. Sebaceous glands are found most often on the scalp, face, and upper body. During adolescence, increased hormone levels enlarge the sebaceous glands and cause them to produce more sebum than usual. The sebum mixes with dead skin cells and forms a plug that closes the follicle openings. This results in a build-up of sebum, followed by an over-development of the bacterial population due to a nutrition rich anaerobic environment. If not treated the bacteria commonly reach toxic levels that sometimes break through the follicle wall and cause inflammation and breakouts on the skin.

As part of its metabolism process P.acnes bacteria secrete a pigment known as porphyrin. When stimulated, porphyrin produces a molecule of singlet oxygen within the follicle. This oxygen in turn attacks the P.acnes bacteria ultimately destroying it. The goal of acne phototherapy therefore, is to stimulate the porphyrin to produce oxygen.

One of the main challenges of acne light therapy has been overcoming the conflict between the depth at which p.acnes and porphyrin are found in the follicle and the relatively shallow penetration depth of the commonly used blue light spectrum.

To optimize the tradeoff between the penetration depth required and the porphyrin activation efficacy LHE utilizes a higher range of the light spectrum including green, yellow and red. It is thought that by offsetting the loss in absorption with a more direct targeting of actual porphyrin less photons are wasted at ineffectual depth penetrations.

Temperature
The Arrhenius equation describes the rate of production of excited porphyrin molecules as a function of temperature. For most chemical reactions elevating the temperature by 10°C will double the speed of the reaction.

By combining direct heat with the light pulse LHE further raises the temperature inside the follicle affecting a much faster chemical reaction time than light alone would generate.

The generated heat also serves to reduce the inflammation, open the pores and soothe the painful lesions often associated with acne.