Papular urticaria in children and adolescents

Lichen urticatus, urticaria papulosa infantum, prurigo simplex acuta, persistent insect bite reaction (papular urticaria).

Chronic recurrent allergic reaction to arthropod bites with persistent, itchy papules in children. No true urticaria.

• Peak age 2-10 years, rarely infants.
• Common in areas with high exposure to insects.
• Association with atopy (asthma, atopic dermatitis).
• Seasonal accumulation (spring/summer), no gender differences.

• Persistent sting reaction, dermatologically belongs to the prurigo group.
• Extreme forms with vesicle formation ("strophulus bullosus").

• Allergic reaction (type I and type IV hypersensitivity) to insect saliva.
• Common triggers: fleas, mosquitoes, bedbugs, mites.
• SCRATCH factors (symmetry, cluster, rover (pets rove in nature), age pediatric, chronology >24h).

• Recurrent, very itchy, grouped papules (3-10 mm), often with a central stitch mark.
• Different stages present at the same time.
• Secondary excoriations due to scratching, no general symptoms.

• Clinical diagnosis is sufficient.
• Typical anamnesis: seasonal, contact with pets, persistence >24h.
• Laboratory usually not necessary; biopsy only if uncertain (eosinophilia).

• Exposed areas (extremities, buttocks, face), symmetrically distributed.
• Clothing-protected areas only rarely affected.

• Recurring episodes in the warm season.
• Connection with pets, travel or insect infestation in the environment.
• Improvement in winter characteristic.
• Parents often report unsuccessful treatment attempts with other diagnoses (e.g. scabies).

• Nonspecific inflammatory infiltrate with numerous eosinophils.
• No specific immunological markers.

• Secondary infections (impetigo contagiosa).
• Severe itching impairs sleep and quality of life.
• Rarely scars after deep excoriations.

• Self-limiting, usually spontaneous remission until adolescence.
• Excellent long-term forecast.

• Minimize exposure to insects (mosquito nets, repellents, flea prophylaxis for pets).
• Optimize home hygiene, early intervention in case of infestation.

1. Celiksoy MH, et al. Prevalence of atopic diseases in children with papular urticaria. Allergol Immunopathol (Madr). 2021;49(1):62-67. DOI:10.15586/aei.v49i1.16
2. Collado-Chagoya R, et al. Specific immunotherapy in patients with papular urticaria by Cimex lectularius: a pilot study. Eur Ann Allergy Clin Immunol. 2021;53(6):282-289. DOI:10.23822/EurAnnACI.1764-1489.215
3. Caffarelli C, et al. The many faces of pediatric urticaria. Front Allergy. 2023;4:1267663. DOI:10.3389/falgy.2023.1267663
4. Schettini N, et al. Urticaria: a narrative overview of differential diagnosis. Biomedicines. 2023;11(4):1096. DOI:10.3390/biomedicines11041096
5. Alraddadi MO, et al. Updates in papular urticaria: causes, diagnosis, and management - a systematic review. Int J Life Sci Pharma Res. 2023;13(1):L57-L65. DOI:10.22376/ijlpr.2023.13.1.SP2.L57-L65
6. Leung AKC, et al. Bed bug infestation: an updated review. Curr Pediatr Rev. 2024;20(2):137-149. DOI:10.2174/1573396320666230406084801
7. Rojo-Gutierrez MI, et al. Urticaria and other mimickers of urticaria. Front Allergy. 2025;5:1522749. DOI:10.3389/falgy.2024.1522749
8. Zuberbier T, et al. S3 Guideline Urticaria, Part 1: Classification and diagnosis (adaptation of the international guideline). J Dtsch Dermatol Ges. 2023;21(1):81-95. DOI:10.1111/ddg.14906_g
9. Oakley A, Koch K. Papular urticaria (persistent insect bite reactions). DermNet New Zealand. Updated Aug 2021 (available online)
10. Singh S, Mann BK. Insect bite reactions (review article). Indian J Dermatol Venereol Leprol. 2013;79(2):151-164. DOI:10.4103/0378-6323.107631 (incl. papular urticaria, historical reference).