Scalds are thermal lesions produced due to contact with moist heat. The moist heat may be either of a hot liquid (water, milk etc.) or its hot vapour.
Because of limited temperature (the maximum possible temperature for a liquid ordinarily, is its boiling point) and because of early cooling of liquids due to evaporation, the lesion due to scald is not very deep. The insulating layer of the skin prevents inward conduction of the heat during the short period for which the hot liquid remains hot. The latent heat (heat retention capacity) of sticky viscid liquids is high and hence the penetration capacity of heat from those liquids is also more. Thus injury caused by hot tar, syrup, oil is comparatively deeper than that caused by hot water.
Features of scald – Scalds produced by water at the boiling point have the following features –
With splashing or pouring of boiling water there is immediate reddening of the area of contact. Within 2-3 minutes, there is blister formation. Surrounding the blister, there is red lining. There is intense burning pain which may lead to primary shock. After the primary shock is overcome, there may be a secondary shock due to hypovolumia, due to loss of body fluid through the blisters. If the scald heals without infection then, there should not be any deep scar formation and contracture. However in case of an extensive scald or in cases of scalds produced by very hot viscid liquid chances remain that there may be a permanent scar, particularly at the central zone, because in case of a very big area being affected, the progress of neo-epithelisation from the periphery to the central zone may take much time during which a portion of the true skin devoid of epithelium may get devitalized. In case of infection, the picture may be totally different and extensive scar may be formed.
The blister may itself get ruptured or may be ruptured for therapeutic reasons. Before blister formation, the affected area appears sodden and bleached. After blister formation the epidermis over the blister appears greyish white. When the blister is ruptured, the floor appears reddish with serosanguinous discharge. Healing of small scalds is complete by 7 – 10 days with formation of temporary scar.
Medicolegal aspects –
1. Scalds are mostly accidental in nature. Scalds may be formed due to accidental spilling or splashing of hot liquid like hot water, milk or oil. It may occur due to careless swallowing of very hot water from a kettle. Often a young child in presence of a careless mother or in her absence may dip a hand in very hot water in a bowl. Accidental scalding may occur in bleaching and dyeing factories.
Homicidal scalding is very very uncommon. But cases are on record where during an altercation one party poured or splashed very hot water on the body of the other. In a few occasions the intolerant mother or the father may ‘punish’ the child by dipping its hand or leg in hot water (battered child syndrome).
Suicidal scalding does-not occur, because it is very painful and there is no guarantee of death.
2. From scalds, time of its occurrence can also be made out (see features of scalds).
3. Blisters may be formed postmortem, both in fresh and decomposed dead bodies. The blisters formed postmortem in a fresh dead body, contains mostly gas or may contain only very little fluid which is not much rich in protein and chloride. Blisters formed during decomposition contains both gas and fluid which is often blood-tinged without any antemortem reaction in and around it. Blisters may also be produced due to application of some irritant plant juice, like that of calotropis or semicarpus plants. They can easily be recognised from their features, including their sizes and distributions. Some systemic drugs or poisons e.g., barbiturate may produce blisters. These cases can be properly diagnosed from accompanying signs and symptoms.
4. Scalds are less fatal and less injurious than burns.
Causes of death in cases of injuries by moist heat –
1. Primary shock – at the very initial phase.
2. Secondary shock – at the middle phase, due to loss of body fluid through the blisters.
3. In case of swallowing of hot liquid – asphyxia, due to swelling and blistering of the area near the upper part of larynx causing choking and later, due to complication like, stricture of oesophagus.
4. In case of inhalation of very hot vapour of some liquid, death may occur from asphyxia due to laryngeal spasm and choking.
5. Infection of extensive scald is a cause of death at the late phase.
Postmortem findings in case of death due to scald –
In cases of death due to scalding, the body will show, externally, the presence of extensive blisters or ruptured blisters with antemortem reaction. In long standing cases, there may be ulcer formation due to infection. If death has occurred due to swallowing of hot liquid or inhalation of hot vapour, signs of gross irritation, oedema and blister formation will be present inside the mouth and near the larynx. In case of death due to shock, there will be minimum other changes. In case of death due to asphyxia, signs in support of the same will be present inside and outside the body.
|1. Causative factor||Dry heat, flame, hot metal||Moist heat, boiling waters, milk, oil, hot vapour|
|2. Appearance||Reddening, blister formation, blackening, charring||Reddening, blister formation, sodden and bleached|
|3. Depth||Often deep upto skin or even more deep||Usually depth is less|
|4. Singeing of hair||Present||Absent|
|5. Site||At and above the site of application of heat||At and below the site of application of heat|
|6. Blister formation||Takes sometime||Occurs within a few minutes|
|7. Splashing or spilling or dribbling mark||Absent||Present|
|8. Sloughing||May occur in deep burns||Usually, does not occur except infection or contact with very hot viscid liquid|
|9. Scar||Permanent when true skin or deeper tissue is involved||Usually no permanent scar without infection or application of very hot viscid liquid|
|10. Contracture||Common||Not common|
|11. Clothes||Burnt||Not burnt|
|12. Medicolegal aspects||Suicidal or accidental, very rarely homicidal||Usually accidental, occasionally homicidal|
|13. Healing||Delayed||Comparatively early|
|14. Fatality||More fatal||Less fatal.|