Viral Exanthem: This is a common cause of rash in children and adults, and a bleeding tongue could be associated with certain viral infections like hand, foot, and mouth disease (HFMD), which is known for causing oral lesions and rashes.

Allergic Reaction: An allergic reaction could cause a rash and, if severe, could lead to oral manifestations including a bleeding tongue, especially if the reaction involves the mucous membranes.
Autoimmune Disorders: Conditions like pemphigus or pemphigoid can cause blistering of the skin and mucous membranes, leading to a rash and potentially a bleeding tongue.
Nutritional Deficiencies: Deficiencies in vitamins like B12 or niacin can cause skin rashes and oral changes, including glossitis, which might lead to a bleeding tongue.

Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN): Although rare, these conditions are life-threatening and can cause severe skin and mucous membrane lesions, including a rash and bleeding tongue, often as a reaction to medications or infections.
Leukemia or Lymphoma: Certain types of blood cancers can cause a rash and oral manifestations, including a bleeding tongue, due to thrombocytopenia or direct infiltration of the tongue.
Infectious Diseases (e.g., Scarlet Fever, Kawasaki Disease): These conditions can present with a rash and oral changes, including a strawberry tongue or bleeding, and require prompt diagnosis and treatment.

Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues, which could potentially lead to easy bruising and bleeding, including in the tongue, along with skin hyperextensibility.
Epidermolysis Bullosa: A rare genetic condition that causes fragile skin and blisters, which could potentially involve the mucous membranes and cause a bleeding tongue.
Pellagra: A disease caused by niacin deficiency, characterized by dermatitis, diarrhea, dementia, and potentially death if left untreated, with oral changes being part of the dermatitis manifestation.