Worldwide, the incidence of second-degree burns is clinically the highest. 

The pathological changes of second-degree burns are very complicated and, until now, quite difficult to manage. 

Second-degree burn is often painful and sensitive to pin-prick. 

The microcirculation in the injured tissue is damaged. Congestion and exudation occur, and a zone of stasis may exist in the dermis. 

When progressive necrosis of the dermal tissue occurs due to microthrombosis formation, this worsens the clinical picture. Second-degree burns destroy the skin barrier and result in a serial systemic reaction and infection. 

Without application of BRT, as epithelial tissue is seriously injured, the wounds healed with disfiguring and painful scar formation, dooming the patient to a lifetime of suffering.

The diagnosis of second-degree burns is not difficult. 

However, with conventional burns treatments, it is difficult to differentiate betwen superficial and deep second-degree burns because the wounds cannot be inspected directly and clearly.

Therefore, the diagnosis is based only on the doctor’s conception of the process and not on direct experience. 

However, when burns regenerative medicine and therapy (MEBT) is applied, there is direct and adequate evidence for establishing the correct diagnosis.

Superficial Second-Degree Burns

Scald Wound. Within 2 h post-scald, obvious color change occurs in the dermis and blisters of different size appear. 

After blister exfoliation, the skin tissue looks moist, slightly red with exudation and has good elasticity. 

Fine hair stands straight and is sensitive to pain when pulled out. The wound is smooth. Two hours later, wound exudate increases with bright red color, and wound swelling (especially wounds in the face) can be observed. 48 h later, swelling subsides and exudate decreases gradually. 

Four days later, epidermis of the wound thickens and the wound heals in about 6 days.

Burns Wound. The wounds may have different appearances according to different causes, e.g. epidermal layer of the wound burned by a gas fire flame has a dark color.

Compared with scald wounds, the wound surface caused by flame is drier and after removal of the blisters, the wound looks dark red, because flame results in serious dehydration. 

Pathological changes in burns wounds caused by flame are the same as in scald wounds.

Deep Second-Degree Burns

Deep second-degree burns may be further differentiated into two subtypes:

(1) superficial subtype of deep second-degree burns with thermal injuries reaching the dermal papilla layer; 

(2) deep subtype of deep second-degree burns with injuries reaching the dermal reticular layer.

The key points to distinguishing the deep second-degree burn from the superficial second-degree burn at the early stage are that in the former, the necrotic layer and the zone of stasis do exist in the dermis of the wound, while in the latter (superficial second-degree burn), there is no formation of either the necrotic layer or the zone of stasis.

Therefore, in the treating procedure, superficial second-degree burns wounds do not have liquefied products of necrotic tissue, while deep second-degree burns wounds produce copious amounts of liquefied products from necrotic tissue before the wound healing.

 The Superficial Subtype of Deep Second-Degree Burns Wounds. The appearance of this type of wound is similar to superficial second-degree burns wounds. 

Scald wounds have blisters of different size and after blister exfoliation, the dermal tissue looks light red or pale with much exu-date. The wound has good elasticity.

24 h later, numerous red pin-spots appear in the pale wound while the superficial layer of the dermis becomes semi-transparent, sensitive to pain, and gives a positive reaction when the hair is pulled out. After the exudation stage, the wound looks red, superficial layer of the dermis begins to liquefy, the base of the wound is in a position lower than skin surface. 

In about 10 days, liquefaction products decrease, the wound grows up to the skin surface. Healing occurs within about 15 days without scar formation. Hyperpigmenta-tion may appear temporarily. After 1 month, the skin color recovers to normal. The burns wounds appear dark or brown in the dermis at the early stage and blisters of different size may exist. 

After removal of the blisters, the dermis looks red alternating with white. Exudate occurs but fine hair disappears. The wound is sensitive to pain, gives positive reaction to needle stab test. After the exudation stage, the wound looks red much as the scald wound does.

The Deep Subtype of Deep Second-Degree Burns Wounds. At the early stage postburn, no blister appears, or small blisters may appear after a while. Scald wounds with no blister have epidermis separated and adhered to the dermis. 

Flame burns wound is dry with black carbonized substances on the epidermis. The wound is obtuse to pain. Some patients even have no pain sensation.

If treated inappropriately, loss of pain sensation will continue, which is an unnecessary and unfortunate consequence. After removal of dead epidermis, the wound looks pale and leathery. In the deep region, dark red spots may be seen. 

The wound surface is dry with less exudate. After the exudation stage, the necrotic layer begins to liquefy. At this point, the wound base is obviously recessed relative to the skin surface. The wound heals to the skin surface in about 25–28 days.