Tetracycline vs. Doxycycline for Acne Treatment - Dermatology

Dr. Zhang Zhibo reply Dermatology

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Hello: To answer your question, we first need to understand the causes of acne, which can be categorized into four main factors:
1.
Hormonal changes and stress lead to increased sebum production.
The sebaceous glands are stimulated by male hormones, producing more sebum, which accumulates in the hair follicles.
This sebum mixes with normal skin bacteria and shed dead skin cells, leading to clogged follicles and the formation of comedones.
Current treatments targeting this cause include oral or topical retinoids and oral anti-androgens (such as contraceptive pills or androgen antagonists).
2.
Abnormal keratinocyte metabolism causes pore blockage.
Blocked follicles can promote bacterial growth, particularly Propionibacterium acnes, which metabolizes sebum and causes it to undergo degeneration.
This irritation can lead to abnormal keratinocyte metabolism, resulting in further blockage of the pores and the formation of comedones.
Available treatments include topical retinoids, azelaic acid, salicylic acid (some skincare products contain 0.5% salicylic acid), and alpha hydroxy acids.
3.
Propionibacterium acnes is normally present on the skin, even in individuals without acne.
It metabolizes sebum, leading to irritation of the pore openings and abnormal keratinocyte metabolism, which can result in clogged pores and the formation of comedones.
If inflammation occurs around the follicle, inflammatory acne lesions can develop.
Treatable options include oral tetracyclines, erythromycin, clindamycin, and topical antibiotics or benzoyl peroxide (BP 5%-10%) to kill bacteria.
Recent findings suggest that low-dose tetracyclines can also have anti-inflammatory effects.
Regarding which tetracycline is better, literature indicates that minocycline is more effective than doxycycline, which in turn is more effective than tetracycline.
However, it is generally not recommended to use a single antibiotic alone; for severe acne, a combination of an oral antibiotic and topical BP is advised to reduce the risk of antibiotic resistance.
4.
Inflammatory processes within the follicles occur due to the presence of Propionibacterium acnes and pore blockage, leading to inflammation within the follicles, which may become hardened, reddened, and even purulent, resulting in acne lesions.
Treatable options include anti-inflammatory medications (typically non-steroidal anti-inflammatory drugs, NSAIDs), but low-dose tetracyclines and topical retinoids also have anti-inflammatory effects.
In addition to these four primary causes, other factors contributing to acne include genetics, cosmetics, environmental influences, and lifestyle habits, as detailed below:
- Genetic factors: Acne can affect individuals of any ethnicity, but there are differences among races; Caucasians tend to experience acne more than Black and Asian individuals.
While everyone can develop acne, some individuals may be predisposed to specific types of acne, which may be similar among family members.
Scientific understanding of the genetic basis of acne is limited, but there appears to be a correlation.
If a teenager's parents or siblings had severe acne, they may be more likely to experience severe acne as well.
- Acne caused by cosmetics: Certain cosmetic ingredients can clog pores and lead to comedones.
These products include makeup, foundation creams, night creams, moisturizers, hair gels, and sunscreens.
Applying more makeup to cover acne can worsen the condition and lead to new comedones.
- Poor diet: While food itself does not directly cause acne, some foods can exacerbate inflammation, such as sweets, chocolate, ice cream, fried foods, and spicy foods.
Therefore, it is advisable for acne patients to limit their intake of these foods, although individual responses may vary.
- Environmental factors: 1.
Occupational exposure to oils and chlorinated hydrocarbons, such as the severe rice bran oil PCB poisoning incident in central Taiwan in 1979, where victims had PCBs in their bodies and skin.
2.
Repeated friction causing inflammation, such as resting the chin on the hands or wearing a helmet that rubs against the face.
3.
Medications, such as anti-tuberculosis drugs (INH), anti-seizure medications (Dilantin), male hormones, steroids, bromides, lithium, and anti-thyroid medications, can trigger acne.
- Irregular lifestyle: Unhealthy routines, excessive stress, poor emotional health, fatigue, insufficient sleep, and poor dietary habits can impair the skin's self-repair mechanisms, leading to increased and worsening acne.
I hope this information is helpful to you.

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Reply Date: 2008/12/02