varalkarapan - Scabies

வரள் கரப்பான் -

The signs and symptoms of Varal karappan  can be correlated with the clinical features of scabies. The Modern aspect of Scabies is discussed here.

Definition:

            It is a form of itching dermatosis  characterized by epidermal burrows, pruritic inflammatory  papules and nodules caused by female sarcoptes scabiei or its products.

PARASITOLOGY:

            Sarcoptes scabiei Var hominis has an oviod body, flattened dorsoventrally. The adult female measures approximately 0.4mm long by 0.3mm broad, and the smaller made 0.2mm long by 0.15mm broad. The body is creamy white and it is marked by transverse corrugations and on its dorsal surface by bristles and spines (denticles). There are four pairs of short legs the anterior two pairs end in elongated peduncles tipped with small suckers. In the female the near two pairs of legs end in long bristles (setae) where as in the male bristles are present on the third pair and elongated peduncles on the fourth.

            Copulation occurs in a small burrow excavated by the female. After copulation, the fertilized  female enlarges the burrow and lays eggs. The burrow is not confined to the stratum corneum, but is inclined   downwards in to the epidermis. Gradual penetration appears to occur as a result of the production of a lytic secretion by the mite, which then proples itself forward as the host tissue is dissolved.  The burrow is lengthened by approximately 2-3mm daily . Eggs and mite faeces are deposited behind the female in the burrow. Six – legged larvae emerge from the eggs after 3 days and escape from the burrow by cutting cay  through its roof. The larvae then dig short burrows (Moulding Pockets) in which they transform into lymphs. After further moults adult males and females develop.

            The mites show a preference for certain sites in which to burrow, and appear to avoid areas with a high density of pilosebaceous follicles. The average number of adult female mites on an individual suffering from the common form of scabies is about 12. Only in crusted (Norwegian) Scabies are large numbers of mites are present.