Tetracyclines

Tetracyclines are an oral antibiotic class: tetracycline, doxycycline, lymecycline and minocycline. In skin disease they are used as much for their anti-inflammatory effect as for killing bacteria. They have the strongest trial evidence for shortening Perioral Dermatitis in adults, along with zero therapy, topical pimecrolimus and topical erythromycin (Hall & Reichenberg 2010). They are also used for steroid-induced rosacea and rebound after stopping strong facial steroids (AFP; Australasian TCS consensus). In the UK, minocycline is no longer started for acne because of lupus-like reactions, pigmentation and hepatitis (Lincolnshire PACEF/NHSE).

Tetracyclines [treats] Perioral Dermatitis Tetracyclines [relates] Topical Steroid Withdrawal

Why toddlers do not get them. Older tetracyclines bind calcium and can permanently stain developing teeth and weaken enamel. In 1970 a warning against use under 8 years was added to the whole class (CDC). Skin sources give different age cut-offs for perioral dermatitis: under 8 (DermNet), under 9 (Cutis 2017) or under 12 (DermNet paediatric page; Australasian TCS consensus). All agree they are unsuitable for 1–4-year-olds. Erythromycin, azithromycin or Clarithromycin are used instead.

Erythromycin [relates] Tetracyclines Tetracyclines [relates] Clarithromycin

Doxycycline nuance. Doxycycline, introduced in 1967, binds calcium less readily. A blinded CDC and Indian Health Service study found no tooth staining or enamel weakness in children given short courses before age 8. The AAP and CDC now recommend doxycycline at any age for suspected rickettsial infections such as Rocky Mountain spotted fever, and the AAP Red Book (2018) allows courses of 21 days or less regardless of age (CDC). This applies to short courses for life-threatening infections. Perioral dermatitis courses usually last 6 weeks or more, so the skin age limits still apply.

Conflict: [DermNet, POD in children, Dec 2018] says avoid oral tetracyclines under 12 years, and [Kellen & Silverberg, Cutis, Dec 2017] say under 9. [CDC / AAP Red Book, 2018] say doxycycline can be used for ≤21 days without regard to age and that short courses do not stain teeth. The sources address different drugs, durations and indications; no source states a safe doxycycline course length for skin disease in under-8s. Unresolved — add to open_questions.

Tetracyclines [relates] Antimicrobial Resistance

Eczema and infection. Tetracyclines are not a routine treatment for eczema or Infected Eczema in children. DermNet lists minocycline as a second-line option for MRSA in older patients, and notes that staphylococci are becoming more resistant to tetracyclines. In an Irish study of 50 children aged 0–7 with AD, tetracycline resistance in their Staphylococcus aureus was 4%, compared with 10% in healthy carriers (not significant; Harkins, BJD 2018).

Tetracyclines [treats] MRSA Staphylococcus aureus [relates] Tetracyclines

Connections

• Perioral Dermatitis — adult first-line, avoided in young children, source: Cutis 2017; DermNet
• Erythromycin — macrolide used instead in young children, source: DermNet 2018
• Clarithromycin — macrolide alternative in children, source: DermNet 2018
• Topical Steroid Withdrawal — used for rebound erythema/steroid rosacea in adults and teenagers, source: AFP; Australasian TCS consensus
• MRSA — minocycline is a second-line option, source: DermNet 2015
• Antimicrobial Resistance — staphylococcal resistance to tetracyclines rising, source: DermNet