Dr Neha Bansal

Definition of Impetigo: It is a bacterial skin infection which is highly contagious. (1) It appears as honey crusted sores. (2)

Age groups affected: It almost exclusively affects pre-school children from 2-5 years. (2) It spreads by direct contact with someone who has the infection. Bullous type occurs mostly in neonates. (1)

Types of Impetigo:
Bullous
Non- bullous (Impetigo Contagiosa)- Predominant type.

Signs & symptoms: Single or multiple erosions along with pustules or blisters with oozing honey-yellow crust are seen. (2) They often start around the nose and face but can spread by auto-inoculation to the arms and legs. The bullous type is a more serious type and present with multiple bullae (2-5 cms) which are thin walled and often rupture and scab. (2) Finding a "collarette" of scale surrounding the ruptured lesion's roof is almost pathognomic of the infection. (1) The diagnosis is mostly clinical rarely requiring culturing to confirm the organism.

Risk Factors for Impetigo: Contaminated water, crowded living conditions, humidity and heat, lack of proper education, lack of personal hygiene and warmer months of summer and autumn. (3)

Causative Organism: Staphylococcus aureus and Group A Beta hemolytic Streptococcus are both responsible for the non bullous type. The bullous type is caused by a staphylococcal toxin which causes breakdown of the epidermis layer of the skin. (1)

Treatment: Impetigo is generally self resolving in 2 weeks. However, treatment results in decrease in discomfort, improved cosmetic appearance of the lesions and prevention of worrisome consequences. (1) There is no standard treatment and various options are available. Topical antibiotics like fusidic acid, Mupirocin 2% ointment are the best line of treatment. (1, 2, 4) Oral Erythromycin has shown increasing rates of resistance and thus now-a-days, either oral azithromycin for 5 days or oral cephalexin for 10 days is the drug of choice. (2)

There is no evidence supporting the effectiveness of topical disinfectants like chlorhexidine and povidone-iodine. (4)

Complications: Often in cases of streptococcus causing impetigo, there is a risk of developing post streptococcal glomerulonephritis. This presents with hypertension and hematuria. (2) Other complications are sepsis, osteomyelitis, arthritis, cellulitis and staphylococcal skin syndrome. (1) Nasal carriers have been implicated in the recurrence of the disease and should be treated with local mupirocin. (2)

REFERENCES

1.		Cole C, Gazewood J. Diagnosis and Treatment of Impetigo. Am Fam Physician 2007;75:859-64,868.
2.		Stulberg DL, Penrod MA, Blatny RA. Common bacterial skin infections Am Fam Physician. 2002 Jul 1;66(1):119-24. Review.
3.		Spurling G, Askew D, King D, Mitchell GK . Bacterial skin infections--an observational study. Aust Fam Physician. 2009 Jul;38(7):547-51.
4.		Koning S Wouden JC. Treatment for impetigo. BMJ 2004;329:695-6