Annular erythema of infancy L30.9

Anular erythema of infancy (AEI) is a benign, rare, idiopathic, figured erythema characterized by varying lengths of persistent, annular, urticarial, non-pruritic patches and plaques that develop in patients < one year of age. Individual lesions may resolve within days without scaling or hyperpigmentation remaining (Kingsley JT et al. 2022).

The etiology of AEI is unknown, but it is thought to be a "hypersensitivity reaction" to an unknown antigen.

The trunk, face and extremities are predominantly affected.

Case report (Kingsley JT et al. 2022)

Systemic mastocytosis was suspected in a 5-month-old boy with a 4-month history of diffuse, nonpruritic erythematous exanthema. Previous viral testing, including herpes simplex virus, Epstein-Barr virus, and cytomegalovirus PCR, was negative. At his last pediatric visit, further laboratory tests revealed an elevated level of eosinophils (4.0%, reference range 0-3.0) without eosinophilia (0.4 k/ul, reference range 0-0.8), elevated serum IgE (123 kU/L, normal ≤30), and elevated tryptase (24.8 mcg/L, normal <11.0). A punch biopsy of the lesion showed mixed dermatitis with numerous eosinophils.

The patient showed no systemic symptoms such as fever or other systemic symptoms. The exanthema was variable and disappeared shortly after a short course of systemic steroids and during a recent middle ear infection.

1. Helm TN et al (1993) Persistent annular erythema of infancy. Pediatr Dermatol 10:46-48.
2. Kingsley JT et al. (2022) A case of annular erythema of infancy accompanied by elevated tryptase. Pediatr Dermatol 39:748-751.
3. Patrizi A et al. (2008) Neutrophilic figurate erythema of infancy. Pediatr Dermatol 25:255-260.
4. Peterson AO Jr et al (1981) Annular erythema of infancy. Arch Dermatol 117:145-148.
5. Tran P et al (2021) Annular Erythema of Infancy With Reactive Helper T Lymphocytes. Cutis 108:289-291.