Medication Summary
Most paronychia infections can be managed without antibiotics; over-the-counter analgesics are usually sufficient. If cellulitis is present, however, then antibiotics are indicated. Although penicillin covers oral flora, it does not cover methicillin-resistant Staphylococcus aureus (MRSA). Trimethoprim and sulfamethoxazole (TMP/SMZ), doxycycline, or clindamycin may be considered to cover community-acquired MRSA and anaerobic organisms. Cephalexin may also be effective. Combination therapy with an intravenous agent that provides antimicrobial activity against staphylococci is used for inpatient therapy.
Chronic paronychial infections are usually managed with oral antifungals such as ketoconazole, itraconazole, or fluconazole. [43] Many of these agents require a prolonged course with monitoring of laboratory tests to avoid complications.
Antibiotics
Class Summary
Therapy must cover all likely pathogens in the context of this clinical setting.
Clindamycin (Cleocin)
This agent is a lincosamide used in the treatment of serious skin and soft tissue staphylococcal infections. It is also effective against aerobic and anaerobic streptococci (except enterococci). Clindamycin inhibits bacterial growth, possibly by blocking the dissociation of peptidyl transfer ribonucleic acid (t-RNA) from ribosomes, causing RNA-dependent protein synthesis to arrest.
Clindamycin widely distributes in the body without penetration of the central nervous system (CNS). It is protein bound and excreted by the liver and kidneys.
Amoxicillin and clavulanic acid (Augmentin, Augmentin XR, Amoclan)
This drug combination is used against bacteria resistant to beta-lactam antibiotics. In children over age 3 months, base dosing protocol on amoxicillin content. Because the amoxicillin/clavulanic acid ratio in 250-mg tablets (250/125) is different than in 250-mg chewable tablets (250/62.5), do not use 250-mg tablets until the child weighs more than 40 kg.
Penicillin VK
Penicillin VK inhibits the biosynthesis of cell wall mucopeptide. It is bactericidal against sensitive organisms when adequate concentrations are reached. It is most effective during the stage of active multiplication. Inadequate concentrations may produce only bacteriostatic effects.
Cephalexin (Keflex)
This is a first-generation cephalosporin that arrests bacterial growth by inhibiting bacterial cell wall synthesis. It has bactericidal activity against rapidly growing organisms, with primary activity against skin flora. It is used for skin infections or for prophylaxis in minor procedures.
Antifungals
Class Summary
The mechanism of action of antifungal agents usually involves the alteration of the permeability of the cell membrane (polyenes) of the fungal cell or the inhibition of pathways (enzymes, substrates, transport) necessary for sterol/cell membrane synthesis.
Miconazole topical (Desenex Spray, Lotrimin AF, Baza Antifungal, Carrington Antifungal, Micaderm, Micatin)
This agent damages the fungal cell wall membrane by inhibiting the biosynthesis of ergosterol. By increasing membrane permeability, it causes nutrients to leak out of the cell, resulting in fungal cell death. Lotion is preferred in intertriginous areas. If cream is used, it should be applied sparingly to avoid maceration effects.
Ketoconazole (Nizoral, Extina, Xologel)
Ketoconazole has fungistatic activity. An imidazole with broad-spectrum antifungal action, it inhibits the synthesis of ergosterol, causing cellular components to leak and resulting in fungal cell death.
Itraconazole (Sporanox, Onmel)
This is a synthetic fungistatic triazole that inhibits cytochrome P-450–dependent synthesis of ergosterol, a vital component of fungal cell membranes.
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Classic presentation of paronychia, with erythema and pus surrounding the nail bed. In this case, the paronychia was due to infection after a hangnail was removed.
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In this case of paronychia, no pus or fluctuance is involved in the nail bed itself.
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Typical appearance of paronychia.
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Depicted are the nail fold (A), dorsal roof (B), ventral floor (C), nail wall (D), perionychium (E), lunula (F), nail bed (G), germinal matrix (H), sterile matrix (I), nail plate (J), hyponychium (K), distal groove (L), fascial septa (M), fat pad (N), distal interphalangeal joint (O), and extensor tendon insertion (P).
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Simple acute paronychia can be drained by elevating the eponychial fold from the nail with a small blunt instrument such as a metal probe or elevator.
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Paronychia incision and drainage.
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Paronychial erythema and edema with associated pustule. This suggests a bacterial etiology.
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Paronychia, side view.
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After simple drainage, there is purulent return.
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Wound opened with a small incision using a number-11 blade scalpel.
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The wound can be explored with a blunt probe, clamps, or the blunt end of a cotton swab.
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Ensure that all loculations are broken up and that as much pus as possible is evacuated.
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Prior to packing or dressing the wound, irrigate the wound with normal saline under pressure, using a splash guard, eye protection, or both.
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The wound can be covered with antibiotic ointment or petroleum jelly to prevent bandage adhesion.
