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ANTIBIOTICS

Antibiotics for specific infections (Fig.4.1) will be discussed in relevant chapters. However, some antibiotics have additional antiinflammatory activity that does not appear to be related to bacterial killing. The main relevant agents include tetracyclines, erythromycin, and some sulfones and sulfonamides (discussed later).

Figure. 4.1 Atypical mycobacterial infection due to Mycobacterium marinum . Unusually, this patient had two primary inoculation sites on the fingers. Clarithromycin is usually effective.

    These agents with antiinflammatory activity are useful in acne and related conditions (Fig. 4.2), in which they also have an antibacterial effect (Ch.10), and may be an adjunct (or occasionally monotherapy) in treatment of immunobullous diseases (Ch.16). In the latter situation, tetracyclines may be used in conjunction with nicotinamide, especially in treatment of bullous pemphigoid. Treatment is typically prolonged, as the antiinflammatory activity takes several weeks to become apparent.

Figure. 4.2 Atypical mycobacterial infection due to Mycobacterium marinum . Unusually, this patient had two primary inoculation sites on the fingers. Clarithromycin is usually effective.

    Side effects from such use are generally not problematic, but candidiasis secondary to tetracyclines, and nausea due to erythromycin, are the commonest limiting factors. If used in conjunction with an oral contraceptive (as occurs quite often in women with acne), many authorities would advise use of additional barrier contraception for the first month.

    Pigmentation due to long-term minocycline is uncommon, especially if treatment is for less than 2 years, but is worthy of attention (Fig. 4.3 and Ch. 18); a lupus erythematosus-like syndrome may also occur with this drug, and blood tests including antinuclear antibody every 6–9 months are prudent.

Figure. 4.3 ( a–f ) Some examples of pigmentation due to minocycline. Although relatively uncommon and specifically related to long-term use of the drug, it is important to be aware of this potential side effect. The color is typically slate-gray; sites affected include the face, nails (c), teeth (d), tongue (e), and old scars (f). Note the normal nail for comparison in (c) and the old acne scars in (e).The pigmentation around the scar (f) occurred at the time of surgery and was thought to be a hematoma. It never resorbed however and this picture is 8 months post surgery. It is thought that minocycline may chelate with the iron of the blood to form a complex that the body is unable to resorb.

White/Cox: Diseases of the Skin, 2ed.(c) 2006, Elsevier Inc. All rights reserved.