Skin diseases and allergic reactions 

Lupus erythematosus is a chronic autoimmune disease in which the immune system attacks healthy tissues, causing inflammation of the skin and multiple organs. The disease ranges from skin-limited discoid lupus erythematosus (DLE) to systemic lupus erythematosus (SLE) involving the kidneys, joints, heart, lungs, nervous system, and blood.

Pemphigus vulgaris is a rare, chronic autoimmune blistering disease characterized by the formation of flaccid blisters and painful erosions involving the skin and mucous membranes. The disease results from autoantibodies directed against proteins responsible for maintaining adhesion between epidermal cells, leading to separation of skin cells (acantholysis) and blister formation.

It is an acute and often life-threatening immunologic reaction, frequently heralded by scalp pruritus, diffuse erythema, urticaria, or angioedema. Bronchospasm, laryngealedema, hyperperistalsis, hypotension, and cardiac arrhythmia may occur. Antiobitics (especially penicillins), other drugs, and radiographic contrast agents are the most common causes of serious anaphylactic reactions.

Scabies is an intensely pruritic and highly contagious infestation of the skin caused by mite Sarcoptes scabies.

It is a common fungal infection of the toes and is often the source of infection at other sites.