• Rare, acute aggressive disseminated proliferative lethal disease of Langerhans cells that affects infants <2 years old.
• Accounts for 10% of cases of Langerhans cell histiocytosis

Clinical features:-

• Initial manifestation often skin rash involving trunk, scalp & extremities.
• Recurrent pyoderma – like lesions with crusting and scaling, vesicopustular and purpuric eruption; resembling seborrhoeic dermatitis.
• Denuded skin may facilitate microbial invasion, leading to sepsis.
• Persistent low grade spiking fever with malaise & irritability.
• Splenomegaly, hepatomegaly & lymphadenopathy are early manifestations.
• Nodular lesions in body flexures and intraoral haemorrhage.
• Myelophthisic anemia , leukopenia and thrombocytopenia may also be seen.
• Bone lesions are not common initially.
• Diffuse involvement of skeletal system occurs later in the disease.
• The uvea may be affected; orbital involvement is most unusual
• The pustules are sterile and Tzanck smear of the vesicopustules shows pale histiocytes which can be used as a rapid screening test.

Oral manifestations:-

• Ulcerative lesions, gingivitis, loose teeth, ectopic teeth also may be seen.
• Parents frequently report precocious eruption of teeth, when in fact the gums are receding to expose immature dentition
• Diffuse destruction of maxilla & mandible.
• Some cases extreme rapid course of disease; oral involvement does not occur.

Histologic Features:-

1.Very similar to HSC; histiocytic proliferation with or without eosinophils.

2.These histiocytes do not contain significant amounts of cholesterol.

3.‘Foam cells’ not a feature.

Treatment & Prognosis:-

• Extremely poor; Course of disease rapid & terminates fatally in short time.
• Poor prognostic features include younger age; dissemination of lesions; involvement of lungs, liver, CNS and RE system; associated infection; anaemia, thrombocytopenia and purpura
• Chemotherapy coupled with radiation to localised bony lesions and supportive measures are useful in treatment.
• Thymic extracts have been successfully used to treat LS disease

References:-

Shafer’s 8th edition