A 57 y.o. male comes in with a complaint of " I think I have poison ivy"

What is the differential?


Our patient had bullous pemphigoid.  Pemphigoid is an autoimmune blistering skin disease. It is different from pemphigus which is also autoimmune but the skin cleaves within the epidermis making the skin very fragile causing sloughing with minor trauma (Nikolsky’s sign) In pemphigoid the blisters are often firm and resist tearing . 

It is the result  of an attack on the basement membrane of the epidermis by immunoglobulins and activated T lymphocytes.  The target is the protein BP180(also called Type XVII collagen) The protein is found in hemidesmosomes, structures the connect the dermis to the epidermis. The binding of antibodies to the hemidesmosomes  destroys them and subepidermal blisters form.

The disease is more prevalent in elderly patients.  It can be triggered by drugs or malignancy.  It is also more common in people with underlying skin disease like psoriasis.

The differential for blistering diseases is broad.

porphyria cutanea tarda in an alcoholic

porphyria cutanea tarda in an alcoholic

AUTOIMMUNE- pemphigoid, and dermatitis herpetiformis  (caused by gluten sensitivity), linear IgA dermatosis, eczema

INFECTIOUS -varicella, herpes, atypical enterovirus infection, necrotising fasciitis, erysipelas.  Reactions to infection like erythema multiforme and staphylococcal scalded skin syndrome also cause blistering .

 DRUGS-Stevens Johnson, fixed drug eruption , drug hypersensitivity syndrome.

CONTACT ALLERGIES- poison ivy, cold exposure

METABOLIC CAUSES- porphyria cutanea tarda (an  abnormality in heme production)

GENETIC CAUSES- epidermolysis bullosa ( a genetic disease resulting in blistering.  Gene therapy has been successfully used in treating this disease in a seven year old boy in Germany. In skin cells from a non blistered area  stem cells were extracted, treated with a virus containing a correct copy of the LAMB3 gene , and grown into sheets which were used to cover his body.  Blistering has not reoccurred in the grafted areas.

epidermolysis bullosa

epidermolysis bullosa

The treatment for bullous pemphigoid is  generally steroids which our patient received.

In 2015  a seven year old boy was  treated for epidermolysis bullosa with gene therapy. The patient’s cells contained a mutation in the LAMB3gene which affects a protein needed to strengthen the epidermi

Wojnarowska F ,Kitschig G, et al. Guidelines for the management of bullous pemphigoid. 2002  Br J Dermatol 147(2) 214-21.

Schmidt E, Zillikens D. The diagnosis and treatment of autoimmune blistering skin diseases. Dtsch Arztebl Int 2011  .  108(23):399-405