Langerhans cell histiocytosis - Anogenital in
LCH is a rare condition, occurring most commonly in White male children aged 1-4 years, but it may present from birth to adulthood. The 3-year survival rate is approximately 80%, with age younger than 2 years, multiorgan involvement, and organ dysfunction portending a worse prognosis.
While 4 clinical variants were previously designated (Letterer-Siwe disease, Hand-Schüller-Christian syndrome, self-healing reticulohistiocytosis of Hashimoto-Pritzker [congenital self-healing histiocytosis], and eosinophilic granuloma), these categories have been largely abandoned in recent years due to significant overlap between the clinical entities and lack of prognostic relevance. Currently, patients are classified based on the number of organ systems involved (ie, single-system or multisystem LCH).
LCH can affect any organ of the body, with bones, skin, oral mucosa, genital mucosa, nail, bone marrow, lungs, liver, spleen, gastrointestinal tract, lymph nodes, and the central nervous system being the most common sites of involvement.
LCH often presents in the first year of life as a rash in the diaper area. Other findings may include lymphadenopathy, diffuse lung involvement, osteolytic involvement of the mastoid presenting with a picture of otitis media, and gastrointestinal involvement. Failure to thrive may be due to malabsorption. There is wide variation in the clinical spectrum. The congenital form presents with papules, nodules, or ulcers at birth; nodules may be solitary or few.
C96.5 – Multifocal and unisystemic Langerhans-cell histiocytosis
C96.6 – Unifocal Langerhans-cell histiocytosis
65399007 – Langerhans cell histiocytosis
Differential Diagnosis & Pitfalls
- Seborrheic dermatitis usually lacks distinct papules. The presence of eroded, ulcerated, or purpuric lesions in a child thought to have seborrheic dermatitis should prompt a biopsy to rule out LCH.
- Psoriasis / infantile psoriasis – Also erythematous and scaly, but not papular or accompanied by systemic symptoms, and usually there is a family history of psoriasis.
- Benign cephalic histiocytosis – Occurs between 2 months and 2 years; on the face and other portions of the head. It is caused by a non-Langerhans cell histiocytosis. Lesions regress spontaneously.
- Scabies may resemble LCH clinically and histologically. Inquire about potentially affected family members.
- Atopic dermatitis is much more pruritic and rapidly responds to topical steroids.
- Diaper dermatitis is localized to the diaper area and responds to gentle skin care and topical steroids.
- Irritant or allergic contact dermatitis
- Herpes simplex