Periungual inflammation: paronychia

 

Paronychia: acute or chronic, what should you do?

Paronychia is inflammation of the tissues surrounding the nail and one of the most common nail disorders. Although different forms may look similar at first, distinguishing acute paronychia from chronic paronychia is essential because their mechanisms and treatment are different.

Practical rule:
Pus or abscess → think acute paronychia.
Loss of the cuticle → think chronic paronychia.

Acute paronychia: look for an abscess

Acute paronychia usually evolves over less than 6 weeks and presents with pain, erythema and swelling of the nail fold. The most common bacterial cause is Staphylococcus aureus, although other possibilities should be remembered, especially herpetic whitlow.

Management depends mainly on one question: is there a purulent collection?

Situation	Practical management
Inflammation without abscess	Warm antiseptic soaks, local treatment and avoidance of further trauma.
Abscess or visible pus	Drainage. Antibiotics do not replace adequate drainage.
Extensive cellulitis, systemic symptoms, immunosuppression or poor clinical course	Consider systemic antibiotic therapy.
Grouped, very painful vesicles	Think herpetic whitlow: DO NOT drain.

Culture is not essential in every case, but it may be useful in significant infection, recurrence, poor response to treatment or when an unusual pathogen is suspected.

Watch out for herpetic whitlow!
Grouped, very painful vesicles without true pus should raise suspicion of herpes simplex virus infection. Incision and drainage should not be performed, as this may promote complications.

Chronic paronychia: it is not simply a Candida infection

When inflammation persists for more than 6 weeks, especially when the proximal nail fold is involved and the cuticle has been lost, chronic paronychia should be considered.

The key to understanding it is to regard it primarily as an irritant or contact dermatitis, promoted by repeated exposure to water, detergents, chemicals and minor trauma. Secondary bacterial or Candida colonisation may occur, but chronic paronychia should not routinely be treated as candidiasis.

This has an important therapeutic consequence: treatment is based on protecting the nail fold and controlling inflammation. Topical corticosteroids are the first-line pharmacological treatment. A clinical trial showed topical methylprednisolone to be superior to systemic itraconazole or terbinafine, supporting the predominantly inflammatory nature of the condition.

Systemic antifungals therefore should not be used routinely and should be reserved for situations in which a relevant fungal infection has been documented.

Key idea: in chronic paronychia, think first of dermatitis and irritants, not a primary fungal infection.

Hand protection is part of the treatment

In chronic paronychia, prescribing a corticosteroid without correcting the triggering factors may lead to treatment failure. Protective measures should be explained to the patient in very practical terms:

• Reduce prolonged or repeated contact with water as much as possible and use waterproof gloves for wet work; if they need to be worn for a prolonged period, cotton gloves can be worn underneath.
• Avoid direct contact with detergents, solvents and other irritants, and dry the hands carefully, especially around the nails.
• Apply emollients several times a day, especially after hand washing.
• Do not cut or manipulate the cuticles: they form a protective barrier between the nail fold and the nail plate.
• Avoid nail biting, pulling hangnails and aggressive manicures.
• Do not keep gloves on unnecessarily when they are damp inside, as sweating can also promote irritation.

Acute versus chronic: quick comparison

Feature	Acute paronychia	Chronic paronychia
Duration	< 6 weeks	> 6 weeks
Main mechanism	Infection, usually bacterial	Inflammation/irritant dermatitis
Clinical clue	Pus / abscess	Loss of the cuticle
Pain	Usually acute and intense	Mild or recurrent
Nail changes	Less common	Beau lines, onychorrhexis
Key treatment	Drain if an abscess is present	Protection + topical corticosteroid

Take-home points

• Acute: before prescribing an antibiotic, ask whether there is an abscess that needs drainage.
• Vesicles: think herpes and do not drain.
• Chronic: think dermatitis, not primary candidiasis.
• Unilateral, refractory chronic paronychia: consider biopsy to exclude other causes, including neoplasia.

Selected references

1. Bacterial and viral infections of the nail unit: Tips for diagnosis and management. Hand Surg Rehabil. 2022. DOI: 10.1016/j.hansur.2022.11.006.
2. Acute and Chronic Paronychia of the Hand. J Am Acad Orthop Surg. 2014. DOI: 10.5435/JAAOS-22-03-165.
3. Tosti A, et al. Topical steroids versus systemic antifungals in the treatment of chronic paronychia. J Am Acad Dermatol. 2002. DOI: 10.1067/mjd.2002.122191.
4. Diagnosis Using the Proximal and Lateral Nail Folds. Dermatol Clin. 2015. DOI: 10.1016/j.det.2014.12.004.