Crusting and Hyperkeratosis in an Infant

Due to atypical presentation, initially we had kept the differential diagnosis of infantile seborrheic dermatitis, impetigo and eczema and even psoriasis. But on follow up, itchy lesion on mother’s hand were noticed incidentally and subsequently the diagnosis was made from skin scrapings which revealed scabies egg and mite fecal matter, confirming the diagnosis of Norwegian scabies.
Human scabies is a parasitic infestation caused by the mite Sarcoptes scabiei var hominis. (1) It induces a marked itching which is mainly nocturnal in typical areas of the body such as flexors folds, cubital margins, axillae, around nipples, navel, external genital organs. Norwegian scabies also called crusted scabies is a rare manifestation of this common parasitic infestation. This is a highly contagious form of scabies due to very high parasitic load. It occurs as a result of the failure of the host immune response (2) or lack of scratching response (3) that helps to remove mites and destroys the burrows. The diagnosis of scabies can be made easily clinically with history and examination alone. But in atypical cases, as in the index case, microscopic evidence of scabies is often necessary to confirm the clinical suspicion. (4) The most common method of diagnosis is microscopic examination of the skin scrapings. (5) Thick crust and extensive scaling with hyperkeratosis are prominent in Norwegian scabies as in our patient. Permethrin is the most preferred drug for the treatment due to its wider safety profile. Patients with crusted scabies may require multiple applications of scabicides as they harbor heavy load of parasites. Though more common in geriatric age group, Norwegian scabies is rarely encountered in pediatric age group. Our patient was treated with overnight application of 5% permethrin lotion and re-application after 2 weeks along with emollients. Both the parents and the infant were treated together. Importance of personal hygiene was also reemphasized. The child is presently under regular weekly follow up and after two applications of permethrin the lesions were almost completely healed.

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